#include <bits/stdc++.h>
using namespace std;
typedef long long int64;
typedef unsigned long long uint64;
const double pi = acos(-1.0);
const double eps = 1e-11;
template <class T>
inline void checkmin(T &a, T b) {
  if (b < a) a = b;
}
template <class T>
inline void checkmax(T &a, T b) {
  if (b > a) a = b;
}
template <class T>
inline T sqr(T x) {
  return x * x;
}
typedef pair<int, int> ipair;
template <class T>
inline T lowbit(T n) {
  return (n ^ (n - 1)) & n;
}
template <class T>
inline int countbit(T n) {
  return (n == 0) ? 0 : (1 + countbit(n & (n - 1)));
}
template <class T>
inline T gcd(T a, T b) {
  if (a < 0) return gcd(-a, b);
  if (b < 0) return gcd(a, -b);
  return (b == 0) ? a : gcd(b, a % b);
}
template <class T>
inline T lcm(T a, T b) {
  if (a < 0) return lcm(-a, b);
  if (b < 0) return lcm(a, -b);
  return a * (b / gcd(a, b));
}
template <class T>
inline T euclide(T a, T b, T &x, T &y) {
  if (a < 0) {
    T d = euclide(-a, b, x, y);
    x = -x;
    return d;
  }
  if (b < 0) {
    T d = euclide(a, -b, x, y);
    y = -y;
    return d;
  }
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  } else {
    T d = euclide(b, a % b, x, y);
    T t = x;
    x = y;
    y = t - (a / b) * y;
    return d;
  }
}
template <class T>
inline vector<pair<T, int> > factorize(T n) {
  vector<pair<T, int> > R;
  for (T i = 2; n > 1;) {
    if (n % i == 0) {
      int C = 0;
      for (; n % i == 0; C++, n /= i)
        ;
      R.push_back(make_pair(i, C));
    }
    i++;
    if (i > n / i) i = n;
  }
  if (n > 1) R.push_back(make_pair(n, 1));
  return R;
}
template <class T>
inline bool isPrimeNumber(T n) {
  if (n <= 1) return false;
  for (T i = 2; i * i <= n; i++)
    if (n % i == 0) return false;
  return true;
}
template <class T>
inline T eularFunction(T n) {
  vector<pair<T, int> > R = factorize(n);
  T r = n;
  for (int i = 0; i < R.size(); i++) r = r / R[i].first * (R[i].first - 1);
  return r;
}
const int MaxMatrixSize = 40;
template <class T>
inline void showMatrix(int n, T A[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) cout << A[i][j];
    cout << endl;
  }
}
template <class T>
inline T checkMod(T n, T m) {
  return (n % m + m) % m;
}
template <class T>
inline void identityMatrix(int n, T A[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) A[i][j] = (i == j) ? 1 : 0;
}
template <class T>
inline void addMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T A[MaxMatrixSize][MaxMatrixSize],
                      T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = A[i][j] + B[i][j];
}
template <class T>
inline void subMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T A[MaxMatrixSize][MaxMatrixSize],
                      T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = A[i][j] - B[i][j];
}
template <class T>
inline void mulMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T _A[MaxMatrixSize][MaxMatrixSize],
                      T _B[MaxMatrixSize][MaxMatrixSize]) {
  T A[MaxMatrixSize][MaxMatrixSize], B[MaxMatrixSize][MaxMatrixSize];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      A[i][j] = _A[i][j], B[i][j] = _B[i][j], C[i][j] = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      for (int k = 0; k < n; k++) C[i][j] += A[i][k] * B[k][j];
}
template <class T>
inline void addModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T A[MaxMatrixSize][MaxMatrixSize],
                         T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = checkMod(A[i][j] + B[i][j], m);
}
template <class T>
inline void subModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T A[MaxMatrixSize][MaxMatrixSize],
                         T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = checkMod(A[i][j] - B[i][j], m);
}
template <class T>
inline T multiplyMod(T a, T b, T m) {
  return (T)((((int64)(a) * (int64)(b) % (int64)(m)) + (int64)(m)) %
             (int64)(m));
}
template <class T>
inline void mulModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T _A[MaxMatrixSize][MaxMatrixSize],
                         T _B[MaxMatrixSize][MaxMatrixSize]) {
  T A[MaxMatrixSize][MaxMatrixSize], B[MaxMatrixSize][MaxMatrixSize];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      A[i][j] = _A[i][j], B[i][j] = _B[i][j], C[i][j] = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      for (int k = 0; k < n; k++)
        C[i][j] = (C[i][j] + multiplyMod(A[i][k], B[k][j], m)) % m;
}
template <class T>
inline T powerMod(T p, int e, T m) {
  if (e == 0)
    return 1 % m;
  else if (e % 2 == 0) {
    T t = powerMod(p, e / 2, m);
    return multiplyMod(t, t, m);
  } else
    return multiplyMod(powerMod(p, e - 1, m), p, m);
}
double dist(double x1, double y1, double x2, double y2) {
  return sqrt(sqr(x1 - x2) + sqr(y1 - y2));
}
double distR(double x1, double y1, double x2, double y2) {
  return sqr(x1 - x2) + sqr(y1 - y2);
}
template <class T>
T cross(T x0, T y0, T x1, T y1, T x2, T y2) {
  return (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0);
}
int crossOper(double x0, double y0, double x1, double y1, double x2,
              double y2) {
  double t = (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0);
  if (fabs(t) <= eps) return 0;
  return (t < 0) ? -1 : 1;
}
bool isIntersect(double x1, double y1, double x2, double y2, double x3,
                 double y3, double x4, double y4) {
  return crossOper(x1, y1, x2, y2, x3, y3) * crossOper(x1, y1, x2, y2, x4, y4) <
             0 &&
         crossOper(x3, y3, x4, y4, x1, y1) * crossOper(x3, y3, x4, y4, x2, y2) <
             0;
}
bool isMiddle(double s, double m, double t) {
  return fabs(s - m) <= eps || fabs(t - m) <= eps || (s < m) != (t < m);
}
bool isUpperCase(char c) { return c >= 'A' && c <= 'Z'; }
bool isLowerCase(char c) { return c >= 'a' && c <= 'z'; }
bool isLetter(char c) { return c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z'; }
bool isDigit(char c) { return c >= '0' && c <= '9'; }
char toLowerCase(char c) { return (isUpperCase(c)) ? (c + 32) : c; }
char toUpperCase(char c) { return (isLowerCase(c)) ? (c - 32) : c; }
template <class T>
string toString(T n) {
  ostringstream ost;
  ost << n;
  ost.flush();
  return ost.str();
}
int toInt(string s) {
  int r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
int64 toInt64(string s) {
  int64 r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
double toDouble(string s) {
  double r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
template <class T>
void stoa(string s, int &n, T A[]) {
  n = 0;
  istringstream sin(s);
  for (T v; sin >> v; A[n++] = v)
    ;
}
template <class T>
void atos(int n, T A[], string &s) {
  ostringstream sout;
  for (int i = 0; i < n; i++) {
    if (i > 0) sout << ' ';
    sout << A[i];
  }
  s = sout.str();
}
template <class T>
void atov(int n, T A[], vector<T> &vi) {
  vi.clear();
  for (int i = 0; i < n; i++) vi.push_back(A[i]);
}
template <class T>
void vtoa(vector<T> vi, int &n, T A[]) {
  n = vi.size();
  for (int i = 0; i < n; i++) A[i] = vi[i];
}
template <class T>
void stov(string s, vector<T> &vi) {
  vi.clear();
  istringstream sin(s);
  for (T v; sin >> v; vi.push_bakc(v))
    ;
}
template <class T>
void vtos(vector<T> vi, string &s) {
  ostringstream sout;
  for (int i = 0; i < vi.size(); i++) {
    if (i > 0) sout << ' ';
    sout << vi[i];
  }
  s = sout.str();
}
template <class T>
struct Fraction {
  T a, b;
  Fraction(T a = 0, T b = 1);
  string toString();
};
template <class T>
Fraction<T>::Fraction(T a, T b) {
  T d = gcd(a, b);
  a /= d;
  b /= d;
  if (b < 0) a = -a, b = -b;
  this->a = a;
  this->b = b;
}
template <class T>
string Fraction<T>::toString() {
  ostringstream sout;
  sout << a << "/" << b;
  return sout.str();
}
template <class T>
Fraction<T> operator+(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b + q.a * p.b, p.b * q.b);
}
template <class T>
Fraction<T> operator-(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b - q.a * p.b, p.b * q.b);
}
template <class T>
Fraction<T> operator*(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.a, p.b * q.b);
}
template <class T>
Fraction<T> operator/(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b, p.b * q.a);
}
int main(void) {
  set<pair<string, string> > s;
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    string a, b;
    cin >> a >> b;
    s.insert(make_pair(a, b));
  }
  cout << s.size() << endl;
}

### Prompt

Your task is to create a cpp solution to the following problem:

Indian summer is such a beautiful time of the year! A girl named Alyona is walking in the forest and picking a bouquet from fallen leaves. Alyona is very choosy — she doesn't take a leaf if it matches the color and the species of the tree of one of the leaves she already has. Find out how many leaves Alyona has picked.

Input

The first line contains an integer n (1 ≤ n ≤ 100) — the number of leaves Alyona has found. The next n lines contain the leaves' descriptions. Each leaf is characterized by the species of the tree it has fallen from and by the color. The species of the trees and colors are given in names, consisting of no more than 10 lowercase Latin letters. A name can not be an empty string. The species of a tree and the color are given in each line separated by a space.

Output

Output the single number — the number of Alyona's leaves.

Examples

Input

5
birch yellow
maple red
birch yellow
maple yellow
maple green


Output

4


Input

3
oak yellow
oak yellow
oak yellow


Output

1

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
typedef long long int64;
typedef unsigned long long uint64;
const double pi = acos(-1.0);
const double eps = 1e-11;
template <class T>
inline void checkmin(T &a, T b) {
  if (b < a) a = b;
}
template <class T>
inline void checkmax(T &a, T b) {
  if (b > a) a = b;
}
template <class T>
inline T sqr(T x) {
  return x * x;
}
typedef pair<int, int> ipair;
template <class T>
inline T lowbit(T n) {
  return (n ^ (n - 1)) & n;
}
template <class T>
inline int countbit(T n) {
  return (n == 0) ? 0 : (1 + countbit(n & (n - 1)));
}
template <class T>
inline T gcd(T a, T b) {
  if (a < 0) return gcd(-a, b);
  if (b < 0) return gcd(a, -b);
  return (b == 0) ? a : gcd(b, a % b);
}
template <class T>
inline T lcm(T a, T b) {
  if (a < 0) return lcm(-a, b);
  if (b < 0) return lcm(a, -b);
  return a * (b / gcd(a, b));
}
template <class T>
inline T euclide(T a, T b, T &x, T &y) {
  if (a < 0) {
    T d = euclide(-a, b, x, y);
    x = -x;
    return d;
  }
  if (b < 0) {
    T d = euclide(a, -b, x, y);
    y = -y;
    return d;
  }
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  } else {
    T d = euclide(b, a % b, x, y);
    T t = x;
    x = y;
    y = t - (a / b) * y;
    return d;
  }
}
template <class T>
inline vector<pair<T, int> > factorize(T n) {
  vector<pair<T, int> > R;
  for (T i = 2; n > 1;) {
    if (n % i == 0) {
      int C = 0;
      for (; n % i == 0; C++, n /= i)
        ;
      R.push_back(make_pair(i, C));
    }
    i++;
    if (i > n / i) i = n;
  }
  if (n > 1) R.push_back(make_pair(n, 1));
  return R;
}
template <class T>
inline bool isPrimeNumber(T n) {
  if (n <= 1) return false;
  for (T i = 2; i * i <= n; i++)
    if (n % i == 0) return false;
  return true;
}
template <class T>
inline T eularFunction(T n) {
  vector<pair<T, int> > R = factorize(n);
  T r = n;
  for (int i = 0; i < R.size(); i++) r = r / R[i].first * (R[i].first - 1);
  return r;
}
const int MaxMatrixSize = 40;
template <class T>
inline void showMatrix(int n, T A[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) cout << A[i][j];
    cout << endl;
  }
}
template <class T>
inline T checkMod(T n, T m) {
  return (n % m + m) % m;
}
template <class T>
inline void identityMatrix(int n, T A[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) A[i][j] = (i == j) ? 1 : 0;
}
template <class T>
inline void addMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T A[MaxMatrixSize][MaxMatrixSize],
                      T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = A[i][j] + B[i][j];
}
template <class T>
inline void subMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T A[MaxMatrixSize][MaxMatrixSize],
                      T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = A[i][j] - B[i][j];
}
template <class T>
inline void mulMatrix(int n, T C[MaxMatrixSize][MaxMatrixSize],
                      T _A[MaxMatrixSize][MaxMatrixSize],
                      T _B[MaxMatrixSize][MaxMatrixSize]) {
  T A[MaxMatrixSize][MaxMatrixSize], B[MaxMatrixSize][MaxMatrixSize];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      A[i][j] = _A[i][j], B[i][j] = _B[i][j], C[i][j] = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      for (int k = 0; k < n; k++) C[i][j] += A[i][k] * B[k][j];
}
template <class T>
inline void addModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T A[MaxMatrixSize][MaxMatrixSize],
                         T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = checkMod(A[i][j] + B[i][j], m);
}
template <class T>
inline void subModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T A[MaxMatrixSize][MaxMatrixSize],
                         T B[MaxMatrixSize][MaxMatrixSize]) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) C[i][j] = checkMod(A[i][j] - B[i][j], m);
}
template <class T>
inline T multiplyMod(T a, T b, T m) {
  return (T)((((int64)(a) * (int64)(b) % (int64)(m)) + (int64)(m)) %
             (int64)(m));
}
template <class T>
inline void mulModMatrix(int n, T m, T C[MaxMatrixSize][MaxMatrixSize],
                         T _A[MaxMatrixSize][MaxMatrixSize],
                         T _B[MaxMatrixSize][MaxMatrixSize]) {
  T A[MaxMatrixSize][MaxMatrixSize], B[MaxMatrixSize][MaxMatrixSize];
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      A[i][j] = _A[i][j], B[i][j] = _B[i][j], C[i][j] = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      for (int k = 0; k < n; k++)
        C[i][j] = (C[i][j] + multiplyMod(A[i][k], B[k][j], m)) % m;
}
template <class T>
inline T powerMod(T p, int e, T m) {
  if (e == 0)
    return 1 % m;
  else if (e % 2 == 0) {
    T t = powerMod(p, e / 2, m);
    return multiplyMod(t, t, m);
  } else
    return multiplyMod(powerMod(p, e - 1, m), p, m);
}
double dist(double x1, double y1, double x2, double y2) {
  return sqrt(sqr(x1 - x2) + sqr(y1 - y2));
}
double distR(double x1, double y1, double x2, double y2) {
  return sqr(x1 - x2) + sqr(y1 - y2);
}
template <class T>
T cross(T x0, T y0, T x1, T y1, T x2, T y2) {
  return (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0);
}
int crossOper(double x0, double y0, double x1, double y1, double x2,
              double y2) {
  double t = (x1 - x0) * (y2 - y0) - (x2 - x0) * (y1 - y0);
  if (fabs(t) <= eps) return 0;
  return (t < 0) ? -1 : 1;
}
bool isIntersect(double x1, double y1, double x2, double y2, double x3,
                 double y3, double x4, double y4) {
  return crossOper(x1, y1, x2, y2, x3, y3) * crossOper(x1, y1, x2, y2, x4, y4) <
             0 &&
         crossOper(x3, y3, x4, y4, x1, y1) * crossOper(x3, y3, x4, y4, x2, y2) <
             0;
}
bool isMiddle(double s, double m, double t) {
  return fabs(s - m) <= eps || fabs(t - m) <= eps || (s < m) != (t < m);
}
bool isUpperCase(char c) { return c >= 'A' && c <= 'Z'; }
bool isLowerCase(char c) { return c >= 'a' && c <= 'z'; }
bool isLetter(char c) { return c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z'; }
bool isDigit(char c) { return c >= '0' && c <= '9'; }
char toLowerCase(char c) { return (isUpperCase(c)) ? (c + 32) : c; }
char toUpperCase(char c) { return (isLowerCase(c)) ? (c - 32) : c; }
template <class T>
string toString(T n) {
  ostringstream ost;
  ost << n;
  ost.flush();
  return ost.str();
}
int toInt(string s) {
  int r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
int64 toInt64(string s) {
  int64 r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
double toDouble(string s) {
  double r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
template <class T>
void stoa(string s, int &n, T A[]) {
  n = 0;
  istringstream sin(s);
  for (T v; sin >> v; A[n++] = v)
    ;
}
template <class T>
void atos(int n, T A[], string &s) {
  ostringstream sout;
  for (int i = 0; i < n; i++) {
    if (i > 0) sout << ' ';
    sout << A[i];
  }
  s = sout.str();
}
template <class T>
void atov(int n, T A[], vector<T> &vi) {
  vi.clear();
  for (int i = 0; i < n; i++) vi.push_back(A[i]);
}
template <class T>
void vtoa(vector<T> vi, int &n, T A[]) {
  n = vi.size();
  for (int i = 0; i < n; i++) A[i] = vi[i];
}
template <class T>
void stov(string s, vector<T> &vi) {
  vi.clear();
  istringstream sin(s);
  for (T v; sin >> v; vi.push_bakc(v))
    ;
}
template <class T>
void vtos(vector<T> vi, string &s) {
  ostringstream sout;
  for (int i = 0; i < vi.size(); i++) {
    if (i > 0) sout << ' ';
    sout << vi[i];
  }
  s = sout.str();
}
template <class T>
struct Fraction {
  T a, b;
  Fraction(T a = 0, T b = 1);
  string toString();
};
template <class T>
Fraction<T>::Fraction(T a, T b) {
  T d = gcd(a, b);
  a /= d;
  b /= d;
  if (b < 0) a = -a, b = -b;
  this->a = a;
  this->b = b;
}
template <class T>
string Fraction<T>::toString() {
  ostringstream sout;
  sout << a << "/" << b;
  return sout.str();
}
template <class T>
Fraction<T> operator+(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b + q.a * p.b, p.b * q.b);
}
template <class T>
Fraction<T> operator-(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b - q.a * p.b, p.b * q.b);
}
template <class T>
Fraction<T> operator*(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.a, p.b * q.b);
}
template <class T>
Fraction<T> operator/(Fraction<T> p, Fraction<T> q) {
  return Fraction<T>(p.a * q.b, p.b * q.a);
}
int main(void) {
  set<pair<string, string> > s;
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    string a, b;
    cin >> a >> b;
    s.insert(make_pair(a, b));
  }
  cout << s.size() << endl;
}

```