#include <bits/stdc++.h>
using namespace std;
struct Fight {
  int x;
  int y;
};
Fight a[10001];
int main() {
  bool f = false, f1 = false;
  int n, x1, y1, k = 0, x2, y2;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a[i].x >> a[i].y;
  }
  if (n == 1 || n == 2) {
    cout << "0";
    return 0;
  }
  if (n == 3) {
    x2 = a[0].x;
    y2 = a[0].y;
    x1 = a[1].x;
    y1 = a[1].y;
    if ((x2 - x1) * (a[2].y - y1) == (y2 - y1) * (a[2].x - x1)) {
      cout << "0";
      return 0;
    }
    cout << "1";
    return 0;
  }
  for (int i = 0; i < n; i++) {
    x2 = a[i].x;
    y2 = a[i].y;
    for (int j = i + 1; j < n; j++) {
      x1 = a[j].x;
      y1 = a[j].y;
      for (int o = j + 1; o < n; o++) {
        if ((x2 - x1) * (a[o].y - y1) != (y2 - y1) * (a[o].x - x1)) {
          k++;
        }
      }
    }
  }
  cout << k;
  return 0;
}
