#include <bits/stdc++.h>
using namespace std;
int x[2011], y[2011];
inline int det(int x1, int y1, int x2, int y2) { return x1 * y2 - x2 * y1; }
int main() {
  int n, tot = 0;
  cin >> n;
  if (n < 3) {
    cout << 0 << endl;
    return 0;
  }
  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 (det(x[j] - x[i], y[j] - y[i], x[k] - x[i], y[k] - y[i]) != 0) tot++;
  cout << tot << endl;
  return 0;
}
