#include <bits/stdc++.h>
using namespace std;
struct Point {
  int x, y;
};
Point pnt[2005];
int n;
long long ans;
int main() {
  scanf("%d", &n);
  ans = 1ll * n * (n - 1) * (n - 2) / 6;
  for (register int i = 1; i <= n; i++) {
    scanf("%d%d", &pnt[i].x, &pnt[i].y);
  }
  for (register int i = 1; i <= n; i++) {
    for (register int j = i + 1; j <= n; j++) {
      for (register int k = j + 1; k <= n; k++) {
        if ((pnt[k].y - pnt[j].y) * (pnt[j].x - pnt[i].x) ==
            (pnt[j].y - pnt[i].y) * (pnt[k].x - pnt[j].x)) {
          ans--;
        }
      }
    }
  }
  printf("%lld\n", ans);
  return 0;
}
