#include <bits/stdc++.h>
using namespace std;
int n, t;
struct node {
  int x;
  int y;
} a[210000];
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) scanf("%d%d", &a[i].x, &a[i].y);
  if (n < 3) return puts("0"), 0;
  for (int i = 1; i <= n; i++)
    for (int j = i + 1; j <= n; j++)
      for (int k = j + 1; k <= n; k++)
        if ((a[j].y - a[i].y) * (a[k].x - a[j].x) ==
            (a[j].x - a[i].x) * (a[k].y - a[j].y))
          continue;
        else
          t++;
  cout << t;
  return 0;
}
