#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<pair<int, int> > vp;
  for (int i = 0; i < n; ++i) {
    int x, y;
    cin >> x >> y;
    vp.push_back(make_pair(x, y));
  }
  int ans = 0;
  for (int i = 0; i < n; ++i) {
    for (int j = i + 1; j < n; ++j) {
      for (int k = j + 1; k < n; ++k) {
        if ((vp[j].second - vp[i].second) * (vp[k].first - vp[j].first) !=
            (vp[k].second - vp[j].second) * (vp[j].first - vp[i].first))
          ans++;
      }
    }
  }
  cout << ans;
  return 0;
}
