#include <bits/stdc++.h>
int main() {
  int n, x[2005], y[2005], i, j, k, x1, x2, y1, y2, p;
  unsigned long long int ans;
  while (scanf("%d", &n) != EOF) {
    for (i = 0; i < n; i++) scanf("%d%d", &x[i], &y[i]);
    if (n < 3)
      printf("0\n");
    else {
      ans = 0;
      for (i = 0; i < n; i++) {
        for (j = i + 1; j < n; j++) {
          x1 = x[i];
          x2 = x[j];
          y1 = y[i];
          y2 = y[j];
          for (k = j + 1; k < n; k++) {
            if (((y[k] - y1) * (x1 - x2)) != ((x[k] - x1) * (y1 - y2))) ans++;
          }
        }
      }
      printf("%llu\n", ans);
    }
  }
  return 0;
}
