#include <bits/stdc++.h>
using namespace std;
int x[2000];
int y[2000];
int main() {
  int n;
  long long sum;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> x[i] >> y[i];
  }
  for (int i = 0; i < n; i++) {
    for (int k = i + 1; k < n; k++) {
      for (int j = k + 1; j < n; j++) {
        if ((x[i] - x[j]) * (y[k] - y[j]) != (x[k] - x[j]) * (y[i] - y[j]))
          sum++;
      }
    }
  }
  cout << sum << endl;
  return 0;
}
