#include <bits/stdc++.h>
int main() {
  int n, i, j, k, no = 0, cont = 0;
  scanf("%d", &n);
  int x[10000], y[10000];
  for (i = 0; i < n; i++) scanf("%d%d", &x[i], &y[i]);
  for (i = 0; i < n - 2; i++) {
    for (j = i + 1; j < n - 1; j++) {
      for (k = j + 1; k < n; k++) {
        if (((y[k] - y[j]) * (x[j] - x[i])) ==
            ((y[j] - y[i]) * (x[k] - x[j]))) {
          no++;
        } else {
          cont++;
        }
      }
    }
  }
  printf("%d", cont);
  return 0;
}
