#include <bits/stdc++.h>
int main() {
  int n;
  int r = 0;
  scanf("%d", &n);
  int table[n][2];
  for (int i = 0; i < n; i++) scanf("%d %d", &table[i][0], &table[i][1]);
  for (int i = 0; i < n - 2; i++) {
    for (int j = i + 1; j < n - 1; j++) {
      int m = table[i][0] - table[j][0];
      int t = table[i][1] - table[j][1];
      for (int k = j + 1; k < n; k++) {
        int p = table[i][0] - table[k][0];
        int q = table[i][1] - table[k][1];
        if (m * q == t * p)
          continue;
        else
          r++;
      }
    }
  }
  printf("%d\n", r);
  return (0);
}
