#include <bits/stdc++.h>
using namespace std;
pair<int, int> p[2005], a, b, c;
int main() {
  long long n, x, y, ans = 0;
  cin >> n;
  p[0] = make_pair(-1000, -1000);
  for (int i = 1; i <= n; i++) {
    cin >> x >> y;
    p[i] = make_pair(x, y);
  }
  sort(p, p + n + 1);
  for (int i = 1; i <= n; i++) {
    a = p[i];
    for (int t = i + 1; t <= n; t++) {
      b = p[t];
      for (int j = t + 1; j <= n; j++) {
        c = p[j];
        if ((c.second - a.second) * (b.first - a.first) !=
            (b.second - a.second) * (c.first - a.first)) {
          ans++;
        }
      }
    }
  }
  cout << ans;
}
