#include <bits/stdc++.h>
using namespace std;
struct node {
  int x, y;
} a[200005];
bool hh(int p, int q, int z) {
  int x1, x2, y1, y2;
  x1 = a[p].x - a[q].x;
  y1 = a[p].y - a[q].y;
  x2 = a[q].x - a[z].x;
  y2 = a[q].y - a[z].y;
  return x1 * y2 != x2 * y1;
}
int main() {
  int n;
  int i, j, k;
  bool t = false;
  scanf("%d", &n);
  for (i = 1; i <= n; i++) scanf("%d%d", &a[i].x, &a[i].y);
  long long s = 0;
  for (i = 1; i <= n - 2; i++)
    for (j = i + 1; j <= n - 1; j++)
      for (k = j + 1; k <= n; k++) {
        t = (hh(i, j, k));
        if (t) s++;
      }
  cout << s << endl;
}
