#include <bits/stdc++.h>
using namespace std;
struct Point {
  int x;
  int y;
};
int crossProduct(Point p1, Point p2, Point p) {
  return (p2.x - p1.x) * (p2.y - p.y) - (p2.y - p1.y) * (p2.x - p.x);
}
int main() {
  Point current;
  int n;
  cin >> n;
  vector<Point> points;
  for (int i = 0; i < n; i++) {
    cin >> current.x >> current.y;
    points.push_back(current);
  }
  int count = 0;
  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      for (int k = j + 1; k < n; k++) {
        if (crossProduct(points[i], points[j], points[k]) != 0) {
          ++count;
        }
      }
    }
  }
  cout << count << "\n";
}
