#include <bits/stdc++.h>
using namespace std;
int n, x[2001], y[2001], res = 0;
int main() {
  ios_base ::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    cin >> x[i] >> y[i];
  }
  for (int i = 1; i <= n; ++i) {
    for (int j = i + 1; j <= n; ++j) {
      for (int k = j + 1; k <= n; ++k) {
        if (x[i] * (y[j] - y[k]) + x[j] * (y[k] - y[i]) +
                x[k] * (y[i] - y[j]) !=
            0) {
          ++res;
        }
      }
    }
  }
  cout << res;
}
