#include <bits/stdc++.h>
using namespace std;
int main() {
  int x[2001], y[2001], n, s = 0;
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> x[i] >> y[i];
  for (int i = 1; i <= n - 2; i++)
    for (int j = i + 1; j <= n - 1; j++)
      for (int k = j + 1; k <= n; k++)
        if (abs(x[i] * (y[j] - y[k]) + x[j] * (y[k] - y[i]) +
                x[k] * (y[i] - y[j])))
          s++;
  cout << s << endl;
}
