#include <bits/stdc++.h>
using namespace std;
struct Point {
  int x;
  int y;
};
int main() {
  int n;
  cin >> n;
  vector<Point> p(n);
  for (int i = 0; i < n; i++) cin >> p[i].x >> p[i].y;
  int triangles = 0;
  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      for (int k = j + 1; k < n; k++) {
        int lhs = (p[j].x - p[i].x) * (p[k].y - p[i].y);
        int rhs = (p[k].x - p[i].x) * (p[j].y - p[i].y);
        if (lhs != rhs) triangles++;
      }
    }
  }
  cout << triangles << endl;
  return 0;
}
