#include <bits/stdc++.h>
int main() {
  int n;
  int i, j, k, x1, x2, x3, y1, y2, y3;
  long int c;
  scanf("%d", &n);
  if (n < 3) {
    printf("0");
  } else {
    c = 0;
    int coord[n][2];
    for (i = 0; i < n; i++) {
      scanf("%d %d", &coord[i][0], &coord[i][1]);
    }
    for (i = 0; i < n; i++) {
      x1 = coord[i][0];
      y1 = coord[i][1];
      for (j = i + 1; j < n; j++) {
        x2 = coord[j][0];
        y2 = coord[j][1];
        for (k = j + 1; k < n; k++) {
          x3 = coord[k][0];
          y3 = coord[k][1];
          if (x1 * y2 + x2 * y3 + x3 * y1 - x2 * y1 - x3 * y2 - x1 * y3 != 0)
            c++;
        }
      }
    }
    printf("%ld", c);
  }
  return 0;
}
