#include <bits/stdc++.h>
using namespace std;
int x[2010], y[2010];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cerr.tie(0);
  int n;
  cin >> n;
  for (auto i = 0; i < (n); i++) cin >> x[i] >> y[i];
  int ans = 0;
  for (auto i = 0; i < (n); i++) {
    for (int j = i + 1; j < n; j++) {
      for (int k = j + 1; k < n; k++) {
        int a = y[i] - y[j];
        int b = x[j] - x[i];
        int c = x[i] * (y[j] - y[i]) + y[i] * (x[i] - x[j]);
        if (a * x[k] + b * y[k] + c) ans++;
      }
    }
  }
  cout << ans << '\n';
  return 0;
}
