#include <bits/stdc++.h>
using namespace std;
int n, ans;
struct node {
  int x, y;
} a[2010];
signed main() {
  scanf("%lld", &n);
  for (int i = 1; i <= n; i++) scanf("%lld %lld", &a[i].x, &a[i].y);
  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 ((a[j].y - a[i].y) * (a[k].x - a[j].x) !=
            (a[k].y - a[j].y) * (a[j].x - a[i].x))
          ans++;
  cout << ans << endl;
  return 0;
}
