#include <bits/stdc++.h>
using namespace std;
struct pt {
  int x, y;
};
double area(int x1, int y1, int x2, int y2, int x3, int y3) {
  return (x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1);
}
double dis(int x1, int y1, int x2, int y2) {
  return 1.0 * sqrt((x1 - y1) * (x1 - y1) + (y1 - y2) * (y1 - y2));
}
const int maxn = 4e6;
int a[maxn + 1], b[maxn + 1];
int main() {
  int n, cnt = 0;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    scanf("%d %d", &a[i], &b[i]);
  }
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      for (int k = j + 1; k <= n; k++) {
        if (area(a[i], b[i], a[j], b[j], a[k], b[k]) != 0) {
          cnt++;
        }
      }
    }
  }
  cout << cnt;
}
