#include <bits/stdc++.h>
int n, a[2005][2], cnt = 0;
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d %d", &a[i][0], &a[i][1]);
  for (int i = 0; i < n - 2; i++)
    for (int j = i + 1; j < n - 1; j++)
      for (int k = j + 1; k < n; k++)
        if ((a[i][1] - a[j][1]) * (a[j][0] - a[k][0]) !=
            (a[j][1] - a[k][1]) * (a[i][0] - a[j][0]))
          cnt++;
  printf("%d\n", cnt);
  return 0;
}
