#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  int x[2010], y[2010];
  cin >> n;
  for (int i = 0; i < n; ++i) cin >> x[i] >> y[i];
  int c = 0;
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < n and j != i; ++j) {
      for (int k = 0; k < n and k != i and k != j; ++k) {
        c += abs(x[i] * (y[j] - y[k]) + x[j] * (y[k] - y[i]) +
                 x[k] * (y[i] - y[j])) != 0;
      }
    }
  }
  cout << c;
  return 0;
}
