#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:36777216")
template <class T>
inline T &RD(T &);
template <class T>
inline void OT(const T &);
inline long long RD() {
  long long x;
  return RD(x);
}
inline double &RF(double &);
inline double RF() {
  double x;
  return RF(x);
}
inline char *RS(char *s);
template <class T0, class T1>
inline T0 &RD(T0 &x0, T1 &x1) {
  RD(x0), RD(x1);
  return x0;
}
template <class T0, class T1, class T2>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2) {
  RD(x0), RD(x1), RD(x2);
  return x0;
}
template <class T0, class T1, class T2, class T3>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3) {
  RD(x0), RD(x1), RD(x2), RD(x3);
  return x0;
}
template <class T0, class T1, class T2, class T3, class T4>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4) {
  RD(x0), RD(x1), RD(x2), RD(x3), RD(x4);
  return x0;
}
template <class T0, class T1, class T2, class T3, class T4, class T5>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5) {
  RD(x0), RD(x1), RD(x2), RD(x3), RD(x4), RD(x5);
  return x0;
}
template <class T0, class T1, class T2, class T3, class T4, class T5, class T6>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5, T6 &x6) {
  RD(x0), RD(x1), RD(x2), RD(x3), RD(x4), RD(x5), RD(x6);
  return x0;
}
template <class T0, class T1>
inline void OT(const T0 &x0, const T1 &x1) {
  OT(x0), OT(x1);
}
template <class T0, class T1, class T2>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2) {
  OT(x0), OT(x1), OT(x2);
}
template <class T0, class T1, class T2, class T3>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3) {
  OT(x0), OT(x1), OT(x2), OT(x3);
}
template <class T0, class T1, class T2, class T3, class T4>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3,
               const T4 &x4) {
  OT(x0), OT(x1), OT(x2), OT(x3), OT(x4);
}
template <class T0, class T1, class T2, class T3, class T4, class T5>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3,
               const T4 &x4, const T5 &x5) {
  OT(x0), OT(x1), OT(x2), OT(x3), OT(x4), OT(x5);
}
template <class T0, class T1, class T2, class T3, class T4, class T5, class T6>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3,
               const T4 &x4, const T5 &x5, const T6 &x6) {
  OT(x0), OT(x1), OT(x2), OT(x3), OT(x4), OT(x5), OT(x6);
}
inline double &RF(double &a, double &b) {
  RF(a), RF(b);
  return a;
}
inline double &RF(double &a, double &b, double &c) {
  RF(a), RF(b), RF(c);
  return a;
}
inline double &RF(double &a, double &b, double &c, double &d) {
  RF(a), RF(b), RF(c), RF(d);
  return a;
}
inline double &RF(double &a, double &b, double &c, double &d, double &e) {
  RF(a), RF(b), RF(c), RF(d), RF(e);
  return a;
}
inline double &RF(double &a, double &b, double &c, double &d, double &e,
                  double &f) {
  RF(a), RF(b), RF(c), RF(d), RF(e), RF(f);
  return a;
}
inline double &RF(double &a, double &b, double &c, double &d, double &e,
                  double &f, double &g) {
  RF(a), RF(b), RF(c), RF(d), RF(e), RF(f), RF(g);
  return a;
}
inline void RS(char *s1, char *s2) { RS(s1), RS(s2); }
inline void RS(char *s1, char *s2, char *s3) { RS(s1), RS(s2), RS(s3); }
template <class T>
inline void RST(T &A) {
  memset(A, 0, sizeof(A));
}
template <class T>
inline void FLC(T &A, int x) {
  memset(A, x, sizeof(A));
}
template <class T>
inline T &SRT(T &A) {
  sort(A.begin(), A.end());
  return A;
}
template <class T, class C>
inline T &SRT(T &A, C B) {
  sort(A.begin(), A.end(), B);
  return A;
}
template <class T>
inline T &UNQ(T &A) {
  A.resize(unique(SRT(A).begin(), SRT(A).end()) - A.begin());
  return A;
}
const int dx4[] = {-1, 0, 1, 0};
const int dy4[] = {0, 1, 0, -1};
const int dx8[] = {-1, 0, 1, 0, -1, -1, 1, 1};
const int dy8[] = {0, 1, 0, -1, -1, 1, -1, 1};
const int dxhorse[] = {-2, -2, -1, -1, 1, 1, 2, 2};
const int dyhorse[] = {1, -1, 2, -2, 2, -2, 1, -1};
const int MOD = 1000000007;
const int INF = 0x3f3f3f3f;
const long long INFF = 1LL << 60;
const double EPS = 1e-9;
const double OO = 1e15;
const double PI = acos(-1.0);
template <class T>
inline void checkMin(T &a, const T b) {
  if (b < a) a = b;
}
template <class T>
inline void checkMax(T &a, const T b) {
  if (a < b) a = b;
}
template <class T>
inline void checkMin(T &a, T &b, const T x) {
  checkMin(a, x), checkMin(b, x);
}
template <class T>
inline void checkMax(T &a, T &b, const T x) {
  checkMax(a, x), checkMax(b, x);
}
template <class T, class C>
inline void checkMin(T &a, const T b, C c) {
  if (c(b, a)) a = b;
}
template <class T, class C>
inline void checkMax(T &a, const T b, C c) {
  if (c(a, b)) a = b;
}
template <class T>
inline T min(T a, T b, T c) {
  return min(min(a, b), c);
}
template <class T>
inline T max(T a, T b, T c) {
  return max(max(a, b), c);
}
template <class T>
inline T min(T a, T b, T c, T d) {
  return min(min(a, b), min(c, d));
}
template <class T>
inline T max(T a, T b, T c, T d) {
  return max(max(a, b), max(c, d));
}
template <class T>
inline T sqr(T a) {
  return a * a;
}
template <class T>
inline T cub(T a) {
  return a * a * a;
}
inline int ceil(int x, int y) { return (x - 1) / y + 1; }
inline int sgn(double x) { return x < -EPS ? -1 : x > EPS; }
inline int sgn(double x, double y) { return sgn(x - y); }
namespace BO {
inline bool _1(int x, int i) { return bool(x & 1 << i); }
inline bool _1(long long x, int i) { return bool(x & 1LL << i); }
inline long long _1(int i) { return 1LL << i; }
template <class T>
inline bool odd(T x) {
  return x & 1;
}
template <class T>
inline bool even(T x) {
  return !odd(x);
}
template <class T>
inline T low_bit(T x) {
  return x & -x;
}
inline int count_bits(int x) { return __builtin_popcount(x); }
inline int count_bits(long long x) { return __builtin_popcountll(x); }
}  // namespace BO
using namespace BO;
namespace NT {
inline void INC(int &a, int b) {
  a += b;
  if (a >= MOD) a -= MOD;
}
inline int sum(int a, int b) {
  a += b;
  if (a >= MOD) a -= MOD;
  return a;
}
inline void DEC(int &a, int b) {
  a -= b;
  if (a < 0) a += MOD;
}
inline int dff(int a, int b) {
  a -= b;
  if (a < 0) a += MOD;
  return a;
}
inline void MUL(int &a, int b) { a = (long long)a * b % MOD; }
inline int pdt(int a, int b) { return (long long)a * b % MOD; }
inline int sum(int a, int b, int c) { return sum(sum(a, b), c); }
inline int sum(int a, int b, int c, int d) { return sum(sum(a, b), sum(c, d)); }
inline int pdt(int a, int b, int c) { return pdt(pdt(a, b), c); }
inline int pdt(int a, int b, int c, int d) { return pdt(pdt(pdt(a, b), c), d); }
inline int pow(int a, int b) {
  int c(1);
  while (b) {
    if (b & 1) MUL(c, a);
    MUL(a, a), b >>= 1;
  }
  return c;
}
inline int pow(int a, long long b) {
  int c(1);
  while (b) {
    if (b & 1) MUL(c, a);
    MUL(a, a), b >>= 1;
  }
  return c;
}
template <class T>
inline T pow(T a, long long b) {
  T c(1);
  while (b) {
    if (b & 1) c *= a;
    a *= a, b >>= 1;
  }
  return c;
}
inline int _I(int b) {
  int a = MOD, x1 = 0, x2 = 1, q;
  while (true) {
    q = a / b, a %= b;
    if (!a) return (x2 + MOD) % MOD;
    DEC(x1, pdt(q, x2));
    q = b / a, b %= a;
    if (!b) return (x1 + MOD) % MOD;
    DEC(x2, pdt(q, x1));
  }
}
inline void DIV(int &a, int b) { MUL(a, _I(b)); }
inline int qtt(int a, int b) { return pdt(a, _I(b)); }
inline int phi(int n) {
  int res = n;
  for (int i = 2; sqr(i) <= n; ++i)
    if (!(n % i)) {
      DEC(res, qtt(res, i));
      do {
        n /= i;
      } while (!(n % i));
    }
  if (n != 1) DEC(res, qtt(res, n));
  return res;
}
}  // namespace NT
using namespace NT;
namespace Math {
long long GCD(long long a, long long b) { return b ? GCD(b, a % b) : a; }
long long extendGCD(long long a, long long b, long long &x, long long &y) {
  if (!b) return x = 1, y = 0, a;
  long long res = extendGCD(b, a % b, x, y), tmp = x;
  x = y, y = tmp - (a / b) * y;
  return res;
}
long long power(long long x, long long k) {
  long long res = 1;
  while (k) {
    if (k & 1) res *= x;
    x *= x, k >>= 1;
  }
  return res;
}
long long powerMod(long long x, long long k, long long m) {
  long long res = 1;
  while (x %= m, k) {
    if (k & 1) res *= x, res %= m;
    x *= x, k >>= 1;
  }
  return res;
}
long long inverse(long long a, long long p, long long t = 1) {
  long long pt = power(p, t);
  long long x, y;
  y = extendGCD(a, pt, x, y);
  return x < 0 ? x += pt : x;
}
long long linearCongruence(long long a, long long b, long long p, long long q) {
  long long x, y;
  y = extendGCD(p, q, x, y);
  while (b < a) b += q / y;
  x *= b - a, x = p * x + a, x %= p * q;
  if (x < 0) x += p * q;
  return x;
}
const int PRIMERANGE = 1000000;
int prime[PRIMERANGE + 1];
int getPrime() {
  memset(prime, 0, sizeof(int) * (PRIMERANGE + 1));
  for (int i = 2; i <= PRIMERANGE; i++) {
    if (!prime[i]) prime[++prime[0]] = i;
    for (int j = 1; j <= prime[0] && prime[j] <= PRIMERANGE / i; j++) {
      prime[prime[j] * i] = 1;
      if (i % prime[j] == 0) break;
    }
  }
  return prime[0];
}
int factor[100][3], facCnt;
int getFactors(int x) {
  facCnt = 0;
  int tmp = x;
  for (int i = 1; prime[i] <= tmp / prime[i]; i++) {
    factor[facCnt][1] = 1, factor[facCnt][2] = 0;
    if (tmp % prime[i] == 0) factor[facCnt][0] = prime[i];
    while (tmp % prime[i] == 0)
      factor[facCnt][2]++, factor[facCnt][1] *= prime[i], tmp /= prime[i];
    if (factor[facCnt][1] > 1) facCnt++;
  }
  if (tmp != 1)
    factor[facCnt][0] = tmp, factor[facCnt][1] = tmp, factor[facCnt++][2] = 1;
  return facCnt;
}
long long combinationModP(long long n, long long k, long long p) {
  if (k > n) return 0;
  if (n - k < k) k = n - k;
  long long a = 1, b = 1, x, y;
  int pcnt = 0;
  for (int i = 1; i <= k; i++) {
    x = n - i + 1, y = i;
    while (x % p == 0) x /= p, pcnt++;
    while (y % p == 0) y /= p, pcnt--;
    x %= p, y %= p, a *= x, b *= y;
    b %= p, a %= p;
  }
  if (pcnt) return 0;
  extendGCD(b, p, x, y);
  if (x < 0) x += p;
  a *= x, a %= p;
  return a;
}
};  // namespace Math
namespace Geo {
const double eps = 1e-8;
int dblcmp(double d) { return d < -eps ? -1 : d > eps; }
int sgn(double a) { return a < -eps ? -1 : a > eps; }
inline double sqr(double x) { return x * x; }
}  // namespace Geo
using namespace Geo;
template <class T>
inline T &RD(T &x) {
  char c;
  for (c = getchar(); c < '-'; c = getchar())
    ;
  if (c == '-') {
    x = '0' - getchar();
    for (c = getchar(); '0' <= c && c <= '9'; c = getchar())
      x = x * 10 + '0' - c;
  } else {
    x = c - '0';
    for (c = getchar(); '0' <= c && c <= '9'; c = getchar())
      x = x * 10 + c - '0';
  }
  return x;
}
inline double &RF(double &x) {
  scanf("%lf", &x);
  return x;
}
inline char *RS(char *s) {
  scanf("%s", s);
  return s;
}
int Case;
template <class T>
inline void OT(const T &x) {
  cout << x << endl;
}
struct point {
  double x, y;
  point() {}
  point(double _x, double _y) : x(_x), y(_y){};
  void input() { scanf("%lf%lf", &x, &y); }
  void output() { printf("%.2f %.2f\n", x, y); }
  bool operator==(point a) const {
    return dblcmp(a.x - x) == 0 && dblcmp(a.y - y) == 0;
  }
  bool operator<(point a) const {
    return dblcmp(a.x - x) == 0 ? dblcmp(y - a.y) < 0 : x < a.x;
  }
  double len() { return hypot(x, y); }
  double len2() { return x * x + y * y; }
  double distance(point p) { return hypot(x - p.x, y - p.y); }
  double distance2(point p) { return sqr(x - p.x) + sqr(y - p.y); }
  point add(point p) { return point(x + p.x, y + p.y); }
  point operator+(const point &p) const { return point(x + p.x, y + p.y); }
  point sub(point p) { return point(x - p.x, y - p.y); }
  point operator-(const point &p) const { return point(x - p.x, y - p.y); }
  point mul(double b) { return point(x * b, y * b); }
  point div(double b) { return point(x / b, y / b); }
  double dot(point p) { return x * p.x + y * p.y; }
  double operator*(const point &p) const { return x * p.x + y * p.y; }
  double det(point p) { return x * p.y - y * p.x; }
};
const int maxp = 1e5 + 9;
struct polygon {
  int n;
  point p[maxp];
  void input() {
    for (int i = 0; i < n; i++) {
      p[i].input();
    }
  }
  void add(point q) { p[n++] = q; }
  struct cmp {
    point p;
    cmp(const point &p0) { p = p0; }
    bool operator()(const point &aa, const point &bb) {
      point a = aa, b = bb;
      int d = dblcmp(a.sub(p).det(b.sub(p)));
      if (d == 0) {
        return dblcmp(a.distance(p) - b.distance(p)) < 0;
      }
      return d > 0;
    }
  };
  void norm() {
    point mi = p[0];
    for (int i = 1; i < n; i++) mi = min(mi, p[i]);
    sort(p, p + n, cmp(mi));
  }
  void getconvex(polygon &convex) {
    int i, j, k;
    sort(p, p + n);
    convex.n = n;
    for (i = 0; i < min(n, 2); i++) {
      convex.p[i] = p[i];
    }
    if (n <= 2) return;
    int &top = convex.n;
    top = 1;
    for (i = 2; i < n; i++) {
      while (top &&
             convex.p[top].sub(p[i]).det(convex.p[top - 1].sub(p[i])) <= 0)
        top--;
      convex.p[++top] = p[i];
    }
    int temp = top;
    convex.p[++top] = p[n - 2];
    for (i = n - 3; i >= 0; i--) {
      while (top != temp &&
             convex.p[top].sub(p[i]).det(convex.p[top - 1].sub(p[i])) <= 0)
        top--;
      convex.p[++top] = p[i];
    }
  }
} P, Q;
int n;
int main() {
  RD(n);
  P.n = 0;
  for (int i = 0; i < n; ++i) {
    double x, y;
    RF(x);
    RF(y);
    P.add(point(x, y - x * x));
  }
  P.getconvex(Q);
  int ans = 0;
  for (int i = 0; i + 1 < Q.n; ++i)
    if (Geo::dblcmp(Q.p[i].x - Q.p[i + 1].x) < 0) ++ans;
  OT(ans);
}

### Prompt

Please create a solution in CPP to the following problem:

Recently Vasya learned that, given two points with different x coordinates, you can draw through them exactly one parabola with equation of type y = x^2 + bx + c, where b and c are reals. Let's call such a parabola an U-shaped one.

Vasya drew several distinct points with integer coordinates on a plane and then drew an U-shaped parabola through each pair of the points that have different x coordinates. The picture became somewhat messy, but Vasya still wants to count how many of the parabolas drawn don't have any drawn point inside their internal area. Help Vasya.

The internal area of an U-shaped parabola is the part of the plane that lies strictly above the parabola when the y axis is directed upwards.

Input

The first line contains a single integer n (1 ≤ n ≤ 100 000) — the number of points.

The next n lines describe the points, the i-th of them contains two integers x_i and y_i — the coordinates of the i-th point. It is guaranteed that all points are distinct and that the coordinates do not exceed 10^6 by absolute value.

Output

In the only line print a single integer — the number of U-shaped parabolas that pass through at least two of the given points and do not contain any of the given points inside their internal area (excluding the parabola itself).

Examples

Input


3
-1 0
0 2
1 0


Output


2


Input


5
1 0
1 -1
0 -1
-1 0
-1 -1


Output


1

Note

On the pictures below all U-shaped parabolas that pass through at least two given points are drawn for each of the examples. The U-shaped parabolas that do not have any given point inside their internal area are drawn in red. 

<image> The first example.  <image> The second example. 

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:36777216")
template <class T>
inline T &RD(T &);
template <class T>
inline void OT(const T &);
inline long long RD() {
  long long x;
  return RD(x);
}
inline double &RF(double &);
inline double RF() {
  double x;
  return RF(x);
}
inline char *RS(char *s);
template <class T0, class T1>
inline T0 &RD(T0 &x0, T1 &x1) {
  RD(x0), RD(x1);
  return x0;
}
template <class T0, class T1, class T2>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2) {
  RD(x0), RD(x1), RD(x2);
  return x0;
}
template <class T0, class T1, class T2, class T3>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3) {
  RD(x0), RD(x1), RD(x2), RD(x3);
  return x0;
}
template <class T0, class T1, class T2, class T3, class T4>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4) {
  RD(x0), RD(x1), RD(x2), RD(x3), RD(x4);
  return x0;
}
template <class T0, class T1, class T2, class T3, class T4, class T5>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5) {
  RD(x0), RD(x1), RD(x2), RD(x3), RD(x4), RD(x5);
  return x0;
}
template <class T0, class T1, class T2, class T3, class T4, class T5, class T6>
inline T0 &RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5, T6 &x6) {
  RD(x0), RD(x1), RD(x2), RD(x3), RD(x4), RD(x5), RD(x6);
  return x0;
}
template <class T0, class T1>
inline void OT(const T0 &x0, const T1 &x1) {
  OT(x0), OT(x1);
}
template <class T0, class T1, class T2>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2) {
  OT(x0), OT(x1), OT(x2);
}
template <class T0, class T1, class T2, class T3>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3) {
  OT(x0), OT(x1), OT(x2), OT(x3);
}
template <class T0, class T1, class T2, class T3, class T4>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3,
               const T4 &x4) {
  OT(x0), OT(x1), OT(x2), OT(x3), OT(x4);
}
template <class T0, class T1, class T2, class T3, class T4, class T5>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3,
               const T4 &x4, const T5 &x5) {
  OT(x0), OT(x1), OT(x2), OT(x3), OT(x4), OT(x5);
}
template <class T0, class T1, class T2, class T3, class T4, class T5, class T6>
inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3,
               const T4 &x4, const T5 &x5, const T6 &x6) {
  OT(x0), OT(x1), OT(x2), OT(x3), OT(x4), OT(x5), OT(x6);
}
inline double &RF(double &a, double &b) {
  RF(a), RF(b);
  return a;
}
inline double &RF(double &a, double &b, double &c) {
  RF(a), RF(b), RF(c);
  return a;
}
inline double &RF(double &a, double &b, double &c, double &d) {
  RF(a), RF(b), RF(c), RF(d);
  return a;
}
inline double &RF(double &a, double &b, double &c, double &d, double &e) {
  RF(a), RF(b), RF(c), RF(d), RF(e);
  return a;
}
inline double &RF(double &a, double &b, double &c, double &d, double &e,
                  double &f) {
  RF(a), RF(b), RF(c), RF(d), RF(e), RF(f);
  return a;
}
inline double &RF(double &a, double &b, double &c, double &d, double &e,
                  double &f, double &g) {
  RF(a), RF(b), RF(c), RF(d), RF(e), RF(f), RF(g);
  return a;
}
inline void RS(char *s1, char *s2) { RS(s1), RS(s2); }
inline void RS(char *s1, char *s2, char *s3) { RS(s1), RS(s2), RS(s3); }
template <class T>
inline void RST(T &A) {
  memset(A, 0, sizeof(A));
}
template <class T>
inline void FLC(T &A, int x) {
  memset(A, x, sizeof(A));
}
template <class T>
inline T &SRT(T &A) {
  sort(A.begin(), A.end());
  return A;
}
template <class T, class C>
inline T &SRT(T &A, C B) {
  sort(A.begin(), A.end(), B);
  return A;
}
template <class T>
inline T &UNQ(T &A) {
  A.resize(unique(SRT(A).begin(), SRT(A).end()) - A.begin());
  return A;
}
const int dx4[] = {-1, 0, 1, 0};
const int dy4[] = {0, 1, 0, -1};
const int dx8[] = {-1, 0, 1, 0, -1, -1, 1, 1};
const int dy8[] = {0, 1, 0, -1, -1, 1, -1, 1};
const int dxhorse[] = {-2, -2, -1, -1, 1, 1, 2, 2};
const int dyhorse[] = {1, -1, 2, -2, 2, -2, 1, -1};
const int MOD = 1000000007;
const int INF = 0x3f3f3f3f;
const long long INFF = 1LL << 60;
const double EPS = 1e-9;
const double OO = 1e15;
const double PI = acos(-1.0);
template <class T>
inline void checkMin(T &a, const T b) {
  if (b < a) a = b;
}
template <class T>
inline void checkMax(T &a, const T b) {
  if (a < b) a = b;
}
template <class T>
inline void checkMin(T &a, T &b, const T x) {
  checkMin(a, x), checkMin(b, x);
}
template <class T>
inline void checkMax(T &a, T &b, const T x) {
  checkMax(a, x), checkMax(b, x);
}
template <class T, class C>
inline void checkMin(T &a, const T b, C c) {
  if (c(b, a)) a = b;
}
template <class T, class C>
inline void checkMax(T &a, const T b, C c) {
  if (c(a, b)) a = b;
}
template <class T>
inline T min(T a, T b, T c) {
  return min(min(a, b), c);
}
template <class T>
inline T max(T a, T b, T c) {
  return max(max(a, b), c);
}
template <class T>
inline T min(T a, T b, T c, T d) {
  return min(min(a, b), min(c, d));
}
template <class T>
inline T max(T a, T b, T c, T d) {
  return max(max(a, b), max(c, d));
}
template <class T>
inline T sqr(T a) {
  return a * a;
}
template <class T>
inline T cub(T a) {
  return a * a * a;
}
inline int ceil(int x, int y) { return (x - 1) / y + 1; }
inline int sgn(double x) { return x < -EPS ? -1 : x > EPS; }
inline int sgn(double x, double y) { return sgn(x - y); }
namespace BO {
inline bool _1(int x, int i) { return bool(x & 1 << i); }
inline bool _1(long long x, int i) { return bool(x & 1LL << i); }
inline long long _1(int i) { return 1LL << i; }
template <class T>
inline bool odd(T x) {
  return x & 1;
}
template <class T>
inline bool even(T x) {
  return !odd(x);
}
template <class T>
inline T low_bit(T x) {
  return x & -x;
}
inline int count_bits(int x) { return __builtin_popcount(x); }
inline int count_bits(long long x) { return __builtin_popcountll(x); }
}  // namespace BO
using namespace BO;
namespace NT {
inline void INC(int &a, int b) {
  a += b;
  if (a >= MOD) a -= MOD;
}
inline int sum(int a, int b) {
  a += b;
  if (a >= MOD) a -= MOD;
  return a;
}
inline void DEC(int &a, int b) {
  a -= b;
  if (a < 0) a += MOD;
}
inline int dff(int a, int b) {
  a -= b;
  if (a < 0) a += MOD;
  return a;
}
inline void MUL(int &a, int b) { a = (long long)a * b % MOD; }
inline int pdt(int a, int b) { return (long long)a * b % MOD; }
inline int sum(int a, int b, int c) { return sum(sum(a, b), c); }
inline int sum(int a, int b, int c, int d) { return sum(sum(a, b), sum(c, d)); }
inline int pdt(int a, int b, int c) { return pdt(pdt(a, b), c); }
inline int pdt(int a, int b, int c, int d) { return pdt(pdt(pdt(a, b), c), d); }
inline int pow(int a, int b) {
  int c(1);
  while (b) {
    if (b & 1) MUL(c, a);
    MUL(a, a), b >>= 1;
  }
  return c;
}
inline int pow(int a, long long b) {
  int c(1);
  while (b) {
    if (b & 1) MUL(c, a);
    MUL(a, a), b >>= 1;
  }
  return c;
}
template <class T>
inline T pow(T a, long long b) {
  T c(1);
  while (b) {
    if (b & 1) c *= a;
    a *= a, b >>= 1;
  }
  return c;
}
inline int _I(int b) {
  int a = MOD, x1 = 0, x2 = 1, q;
  while (true) {
    q = a / b, a %= b;
    if (!a) return (x2 + MOD) % MOD;
    DEC(x1, pdt(q, x2));
    q = b / a, b %= a;
    if (!b) return (x1 + MOD) % MOD;
    DEC(x2, pdt(q, x1));
  }
}
inline void DIV(int &a, int b) { MUL(a, _I(b)); }
inline int qtt(int a, int b) { return pdt(a, _I(b)); }
inline int phi(int n) {
  int res = n;
  for (int i = 2; sqr(i) <= n; ++i)
    if (!(n % i)) {
      DEC(res, qtt(res, i));
      do {
        n /= i;
      } while (!(n % i));
    }
  if (n != 1) DEC(res, qtt(res, n));
  return res;
}
}  // namespace NT
using namespace NT;
namespace Math {
long long GCD(long long a, long long b) { return b ? GCD(b, a % b) : a; }
long long extendGCD(long long a, long long b, long long &x, long long &y) {
  if (!b) return x = 1, y = 0, a;
  long long res = extendGCD(b, a % b, x, y), tmp = x;
  x = y, y = tmp - (a / b) * y;
  return res;
}
long long power(long long x, long long k) {
  long long res = 1;
  while (k) {
    if (k & 1) res *= x;
    x *= x, k >>= 1;
  }
  return res;
}
long long powerMod(long long x, long long k, long long m) {
  long long res = 1;
  while (x %= m, k) {
    if (k & 1) res *= x, res %= m;
    x *= x, k >>= 1;
  }
  return res;
}
long long inverse(long long a, long long p, long long t = 1) {
  long long pt = power(p, t);
  long long x, y;
  y = extendGCD(a, pt, x, y);
  return x < 0 ? x += pt : x;
}
long long linearCongruence(long long a, long long b, long long p, long long q) {
  long long x, y;
  y = extendGCD(p, q, x, y);
  while (b < a) b += q / y;
  x *= b - a, x = p * x + a, x %= p * q;
  if (x < 0) x += p * q;
  return x;
}
const int PRIMERANGE = 1000000;
int prime[PRIMERANGE + 1];
int getPrime() {
  memset(prime, 0, sizeof(int) * (PRIMERANGE + 1));
  for (int i = 2; i <= PRIMERANGE; i++) {
    if (!prime[i]) prime[++prime[0]] = i;
    for (int j = 1; j <= prime[0] && prime[j] <= PRIMERANGE / i; j++) {
      prime[prime[j] * i] = 1;
      if (i % prime[j] == 0) break;
    }
  }
  return prime[0];
}
int factor[100][3], facCnt;
int getFactors(int x) {
  facCnt = 0;
  int tmp = x;
  for (int i = 1; prime[i] <= tmp / prime[i]; i++) {
    factor[facCnt][1] = 1, factor[facCnt][2] = 0;
    if (tmp % prime[i] == 0) factor[facCnt][0] = prime[i];
    while (tmp % prime[i] == 0)
      factor[facCnt][2]++, factor[facCnt][1] *= prime[i], tmp /= prime[i];
    if (factor[facCnt][1] > 1) facCnt++;
  }
  if (tmp != 1)
    factor[facCnt][0] = tmp, factor[facCnt][1] = tmp, factor[facCnt++][2] = 1;
  return facCnt;
}
long long combinationModP(long long n, long long k, long long p) {
  if (k > n) return 0;
  if (n - k < k) k = n - k;
  long long a = 1, b = 1, x, y;
  int pcnt = 0;
  for (int i = 1; i <= k; i++) {
    x = n - i + 1, y = i;
    while (x % p == 0) x /= p, pcnt++;
    while (y % p == 0) y /= p, pcnt--;
    x %= p, y %= p, a *= x, b *= y;
    b %= p, a %= p;
  }
  if (pcnt) return 0;
  extendGCD(b, p, x, y);
  if (x < 0) x += p;
  a *= x, a %= p;
  return a;
}
};  // namespace Math
namespace Geo {
const double eps = 1e-8;
int dblcmp(double d) { return d < -eps ? -1 : d > eps; }
int sgn(double a) { return a < -eps ? -1 : a > eps; }
inline double sqr(double x) { return x * x; }
}  // namespace Geo
using namespace Geo;
template <class T>
inline T &RD(T &x) {
  char c;
  for (c = getchar(); c < '-'; c = getchar())
    ;
  if (c == '-') {
    x = '0' - getchar();
    for (c = getchar(); '0' <= c && c <= '9'; c = getchar())
      x = x * 10 + '0' - c;
  } else {
    x = c - '0';
    for (c = getchar(); '0' <= c && c <= '9'; c = getchar())
      x = x * 10 + c - '0';
  }
  return x;
}
inline double &RF(double &x) {
  scanf("%lf", &x);
  return x;
}
inline char *RS(char *s) {
  scanf("%s", s);
  return s;
}
int Case;
template <class T>
inline void OT(const T &x) {
  cout << x << endl;
}
struct point {
  double x, y;
  point() {}
  point(double _x, double _y) : x(_x), y(_y){};
  void input() { scanf("%lf%lf", &x, &y); }
  void output() { printf("%.2f %.2f\n", x, y); }
  bool operator==(point a) const {
    return dblcmp(a.x - x) == 0 && dblcmp(a.y - y) == 0;
  }
  bool operator<(point a) const {
    return dblcmp(a.x - x) == 0 ? dblcmp(y - a.y) < 0 : x < a.x;
  }
  double len() { return hypot(x, y); }
  double len2() { return x * x + y * y; }
  double distance(point p) { return hypot(x - p.x, y - p.y); }
  double distance2(point p) { return sqr(x - p.x) + sqr(y - p.y); }
  point add(point p) { return point(x + p.x, y + p.y); }
  point operator+(const point &p) const { return point(x + p.x, y + p.y); }
  point sub(point p) { return point(x - p.x, y - p.y); }
  point operator-(const point &p) const { return point(x - p.x, y - p.y); }
  point mul(double b) { return point(x * b, y * b); }
  point div(double b) { return point(x / b, y / b); }
  double dot(point p) { return x * p.x + y * p.y; }
  double operator*(const point &p) const { return x * p.x + y * p.y; }
  double det(point p) { return x * p.y - y * p.x; }
};
const int maxp = 1e5 + 9;
struct polygon {
  int n;
  point p[maxp];
  void input() {
    for (int i = 0; i < n; i++) {
      p[i].input();
    }
  }
  void add(point q) { p[n++] = q; }
  struct cmp {
    point p;
    cmp(const point &p0) { p = p0; }
    bool operator()(const point &aa, const point &bb) {
      point a = aa, b = bb;
      int d = dblcmp(a.sub(p).det(b.sub(p)));
      if (d == 0) {
        return dblcmp(a.distance(p) - b.distance(p)) < 0;
      }
      return d > 0;
    }
  };
  void norm() {
    point mi = p[0];
    for (int i = 1; i < n; i++) mi = min(mi, p[i]);
    sort(p, p + n, cmp(mi));
  }
  void getconvex(polygon &convex) {
    int i, j, k;
    sort(p, p + n);
    convex.n = n;
    for (i = 0; i < min(n, 2); i++) {
      convex.p[i] = p[i];
    }
    if (n <= 2) return;
    int &top = convex.n;
    top = 1;
    for (i = 2; i < n; i++) {
      while (top &&
             convex.p[top].sub(p[i]).det(convex.p[top - 1].sub(p[i])) <= 0)
        top--;
      convex.p[++top] = p[i];
    }
    int temp = top;
    convex.p[++top] = p[n - 2];
    for (i = n - 3; i >= 0; i--) {
      while (top != temp &&
             convex.p[top].sub(p[i]).det(convex.p[top - 1].sub(p[i])) <= 0)
        top--;
      convex.p[++top] = p[i];
    }
  }
} P, Q;
int n;
int main() {
  RD(n);
  P.n = 0;
  for (int i = 0; i < n; ++i) {
    double x, y;
    RF(x);
    RF(y);
    P.add(point(x, y - x * x));
  }
  P.getconvex(Q);
  int ans = 0;
  for (int i = 0; i + 1 < Q.n; ++i)
    if (Geo::dblcmp(Q.p[i].x - Q.p[i + 1].x) < 0) ++ans;
  OT(ans);
}

```