#include <bits/stdc++.h>
struct node {
  int x, y;
} h[20005];
int kk(int x1, int y1, int x2, int y2, int x3, int y3) {
  return ((x2 * y3 + x1 * y2 + x3 * y1 - x3 * y2 - x2 * y1 - x1 * y3));
}
int main() {
  int a, b, c, d, e, f;
  scanf("%d", &a);
  for (b = 1; b <= a; b++) {
    scanf("%d %d", &h[b].x, &h[b].y);
  }
  f = 0;
  for (c = 1; c <= a; c++) {
    for (d = c + 1; d <= a; d++) {
      for (e = d + 1; e <= a; e++) {
        if (kk(h[e].x, h[e].y, h[c].x, h[c].y, h[d].x, h[d].y)) f++;
      }
    }
  }
  printf("%d\n", f);
  return 0;
}
