#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T sqr(T x) {
  return x * x;
}
template <class T>
inline T parse(const string &s) {
  T x;
  stringstream ss(s);
  ss >> x;
  return x;
}
const double EPS = 1e-12;
const int INF = 1000 * 1000 * 1000;
const long long LINF = INF * 1ll * INF;
const double DINF = 1e200;
const double PI = 3.1415926535897932384626433832795l;
int gcd(int a, int b) { return a ? gcd(b % a, a) : b; }
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long gcdex(long long a, long long b, long long &x, long long &y) {
  if (!a) {
    x = 0, y = 1;
    return b;
  }
  long long k = b / a;
  long long g = gcdex(b - k * a, a, y, x);
  x -= k * y;
  return g;
}
long long inv(long long a, long long m) {
  assert(m > 1);
  long long x, y, g;
  g = gcdex(a, m, x, y);
  return (x % (m / g) + m / g) % m / g;
}
long long crt(long long a1, long long m1, long long a2, long long m2) {
  long long a = (a2 - a1 % m2 + m2) % m2;
  long long x, y, g;
  g = gcdex(m1, m2, x, y);
  if (a % g) return -1;
  long long m = m1 / g * m2;
  assert(x + m2 >= 0);
  x = a / g * (x + m2) % m2;
  long long r = (a1 + x * m1) % m;
  assert(r % m1 == a1 && r % m2 == a2);
  return r;
}
long long powmod(long long a, long long p, long long m) {
  assert(p >= 0);
  long long r = 1;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
bool isprime(long long a) {
  if (a <= 1) return false;
  for (long long i = 2; i * i <= a; ++i) {
    if (a % i == 0) return false;
  }
  return true;
}
long long sqrtup(long long a) {
  if (!a) return 0;
  long long x = max(0ll, (long long)sqrt((double)a));
  while (x * x >= a) --x;
  while ((x + 1) * (x + 1) < a) ++x;
  return x + 1;
}
long long isqrt(long long a) {
  if (a <= 0) {
    assert(!a);
    return 0;
  }
  long long x = (long long)sqrt((double)a);
  while (sqr(x + 1) <= a) ++x;
  while (x * x > a) --x;
  return x;
}
long long sgn(long long x) { return x < 0 ? -1 : x > 0 ? 1 : 0; }
double randf() {
  double m = RAND_MAX + 1.;
  return (((rand() + .5) / m + rand()) / m + rand()) / m;
}
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v);
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p);
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m);
template <class T>
ostream &operator<<(ostream &s, const set<T> &m);
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a);
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t);
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v) {
  s << '[';
  for (int i = 0; i < (((int)(v).size())); ++i) {
    if (i) s << ',';
    s << v[i];
  }
  s << ']';
  return s;
}
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p) {
  s << "(" << p.first << "," << p.second << ")";
  return s;
}
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it.first << ": " << it.second;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const set<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const multiset<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T, class V, class C>
ostream &operator<<(ostream &s, const priority_queue<T, V, C> &q) {
  auto a = q;
  s << "{";
  bool f = false;
  while (!a.empty()) {
    if (f) s << ",";
    f = true;
    s << a.top();
    a.pop();
  }
  return s << "}";
}
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const deque<T> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <size_t n, class... T>
struct put1 {
  static ostream &put(ostream &s, const tuple<T...> &t) {
    s << get<sizeof...(T) - n>(t);
    if (n > 1) s << ',';
    return put1<n - 1, T...>::put(s, t);
  }
};
template <class... T>
struct put1<0, T...> {
  static ostream &put(ostream &s, const tuple<T...> &t) { return s; }
};
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t) {
  s << "(";
  put1<sizeof...(T), T...>::put(s, t);
  s << ")";
  return s;
}
ostream &put3(ostream &s, const char *, bool) { return s; }
template <class U, class... T>
ostream &put3(ostream &s, const char *f, bool fs, U &&u, T &&...t) {
  while (*f == ' ') ++f;
  if (!fs) s << ", ";
  auto nf = f;
  int d = 0;
  while (*nf && (*nf != ',' || d)) {
    if (*nf == '(')
      ++d;
    else if (*nf == ')')
      --d;
    ++nf;
  }
  auto nf2 = nf;
  while (nf2 > f && *(nf2 - 1) == ' ') --nf;
  fs = *f == '"';
  if (!fs) {
    s.write(f, nf2 - f);
    s << "=";
  };
  s << u;
  if (fs) s << ' ';
  if (*nf) ++nf;
  return put3(s, nf, fs, forward<T>(t)...);
}
int main(int argc, char **argv) {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(20);
  srand(35964);
  int n;
  cin >> n;
  vector<pair<long long, long long> > A(n);
  for (int i = 0; i < (n); ++i) cin >> A[i].first >> A[i].second;
  sort((A).begin(), (A).end());
  vector<pair<long long, long long> > R;
  auto ok = [](pair<long long, long long> a, pair<long long, long long> b,
               pair<long long, long long> c) {
    if (c.first == b.first) return false;
    if (a.first == b.first) return true;
    double bb =
        (a.second - b.second) * 1. / (a.first - b.first) - (a.first + b.first);
    double cc = a.second - a.first * a.first - bb * a.first;
    return c.second < -EPS + c.first * c.first + c.first * bb + cc;
  };
  for (pair<long long, long long> p : A) {
    while (((int)(R).size()) > 1 && !ok(R[((int)(R).size()) - 2], R.back(), p))
      R.pop_back();
    R.push_back(p);
  }
  do {
  } while (false);
  if (((int)(R).size()) > 1 && R[0].first == R[1].first) {
    assert(((int)(R).size()) == 2 || R[2].first > R[1].first);
    R.erase(R.begin());
  }
  cout << ((int)(R).size()) - 1;
  return 0;
}

### Prompt

Your task is to create a Cpp solution 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;
template <class T>
inline T sqr(T x) {
  return x * x;
}
template <class T>
inline T parse(const string &s) {
  T x;
  stringstream ss(s);
  ss >> x;
  return x;
}
const double EPS = 1e-12;
const int INF = 1000 * 1000 * 1000;
const long long LINF = INF * 1ll * INF;
const double DINF = 1e200;
const double PI = 3.1415926535897932384626433832795l;
int gcd(int a, int b) { return a ? gcd(b % a, a) : b; }
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long gcdex(long long a, long long b, long long &x, long long &y) {
  if (!a) {
    x = 0, y = 1;
    return b;
  }
  long long k = b / a;
  long long g = gcdex(b - k * a, a, y, x);
  x -= k * y;
  return g;
}
long long inv(long long a, long long m) {
  assert(m > 1);
  long long x, y, g;
  g = gcdex(a, m, x, y);
  return (x % (m / g) + m / g) % m / g;
}
long long crt(long long a1, long long m1, long long a2, long long m2) {
  long long a = (a2 - a1 % m2 + m2) % m2;
  long long x, y, g;
  g = gcdex(m1, m2, x, y);
  if (a % g) return -1;
  long long m = m1 / g * m2;
  assert(x + m2 >= 0);
  x = a / g * (x + m2) % m2;
  long long r = (a1 + x * m1) % m;
  assert(r % m1 == a1 && r % m2 == a2);
  return r;
}
long long powmod(long long a, long long p, long long m) {
  assert(p >= 0);
  long long r = 1;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
bool isprime(long long a) {
  if (a <= 1) return false;
  for (long long i = 2; i * i <= a; ++i) {
    if (a % i == 0) return false;
  }
  return true;
}
long long sqrtup(long long a) {
  if (!a) return 0;
  long long x = max(0ll, (long long)sqrt((double)a));
  while (x * x >= a) --x;
  while ((x + 1) * (x + 1) < a) ++x;
  return x + 1;
}
long long isqrt(long long a) {
  if (a <= 0) {
    assert(!a);
    return 0;
  }
  long long x = (long long)sqrt((double)a);
  while (sqr(x + 1) <= a) ++x;
  while (x * x > a) --x;
  return x;
}
long long sgn(long long x) { return x < 0 ? -1 : x > 0 ? 1 : 0; }
double randf() {
  double m = RAND_MAX + 1.;
  return (((rand() + .5) / m + rand()) / m + rand()) / m;
}
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v);
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p);
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m);
template <class T>
ostream &operator<<(ostream &s, const set<T> &m);
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a);
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t);
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v) {
  s << '[';
  for (int i = 0; i < (((int)(v).size())); ++i) {
    if (i) s << ',';
    s << v[i];
  }
  s << ']';
  return s;
}
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p) {
  s << "(" << p.first << "," << p.second << ")";
  return s;
}
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it.first << ": " << it.second;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const set<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const multiset<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T, class V, class C>
ostream &operator<<(ostream &s, const priority_queue<T, V, C> &q) {
  auto a = q;
  s << "{";
  bool f = false;
  while (!a.empty()) {
    if (f) s << ",";
    f = true;
    s << a.top();
    a.pop();
  }
  return s << "}";
}
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const deque<T> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <size_t n, class... T>
struct put1 {
  static ostream &put(ostream &s, const tuple<T...> &t) {
    s << get<sizeof...(T) - n>(t);
    if (n > 1) s << ',';
    return put1<n - 1, T...>::put(s, t);
  }
};
template <class... T>
struct put1<0, T...> {
  static ostream &put(ostream &s, const tuple<T...> &t) { return s; }
};
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t) {
  s << "(";
  put1<sizeof...(T), T...>::put(s, t);
  s << ")";
  return s;
}
ostream &put3(ostream &s, const char *, bool) { return s; }
template <class U, class... T>
ostream &put3(ostream &s, const char *f, bool fs, U &&u, T &&...t) {
  while (*f == ' ') ++f;
  if (!fs) s << ", ";
  auto nf = f;
  int d = 0;
  while (*nf && (*nf != ',' || d)) {
    if (*nf == '(')
      ++d;
    else if (*nf == ')')
      --d;
    ++nf;
  }
  auto nf2 = nf;
  while (nf2 > f && *(nf2 - 1) == ' ') --nf;
  fs = *f == '"';
  if (!fs) {
    s.write(f, nf2 - f);
    s << "=";
  };
  s << u;
  if (fs) s << ' ';
  if (*nf) ++nf;
  return put3(s, nf, fs, forward<T>(t)...);
}
int main(int argc, char **argv) {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(20);
  srand(35964);
  int n;
  cin >> n;
  vector<pair<long long, long long> > A(n);
  for (int i = 0; i < (n); ++i) cin >> A[i].first >> A[i].second;
  sort((A).begin(), (A).end());
  vector<pair<long long, long long> > R;
  auto ok = [](pair<long long, long long> a, pair<long long, long long> b,
               pair<long long, long long> c) {
    if (c.first == b.first) return false;
    if (a.first == b.first) return true;
    double bb =
        (a.second - b.second) * 1. / (a.first - b.first) - (a.first + b.first);
    double cc = a.second - a.first * a.first - bb * a.first;
    return c.second < -EPS + c.first * c.first + c.first * bb + cc;
  };
  for (pair<long long, long long> p : A) {
    while (((int)(R).size()) > 1 && !ok(R[((int)(R).size()) - 2], R.back(), p))
      R.pop_back();
    R.push_back(p);
  }
  do {
  } while (false);
  if (((int)(R).size()) > 1 && R[0].first == R[1].first) {
    assert(((int)(R).size()) == 2 || R[2].first > R[1].first);
    R.erase(R.begin());
  }
  cout << ((int)(R).size()) - 1;
  return 0;
}

```