#include <bits/stdc++.h>
using namespace std;
const int INF = numeric_limits<int>::max();
const long long LLINF = numeric_limits<long long>::max();
const unsigned long long ULLINF = numeric_limits<unsigned long long>::max();
void solve() {
  int n;
  cin >> n;
  vector<pair<int, int>> pn;
  for (int i = 0; i < n; ++i) {
    int x, y;
    cin >> x >> y;
    pn.push_back(make_pair(x, y));
  }
  long long 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 ((pn[i].first - pn[k].first) * (pn[j].second - pn[i].second) -
            (pn[i].first - pn[j].first) * (pn[k].second - pn[i].second))
          ++ans;
  cout << ans;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int t = 1;
  while (t--) solve();
  return 0;
}
