#include <bits/stdc++.h>
using namespace std;
struct Point {
  double x, y;
} pts[2000];
int n;
double dis(Point a, Point b) {
  return sqrt(pow(a.x - b.x, 2) + pow(a.y - b.y, 2));
}
double area(Point a, Point b, Point c) {
  Point ba, ca;
  ba.x = b.x - a.x;
  ba.y = b.y - a.y;
  ca.x = c.x - a.x;
  ca.y = c.y - a.y;
  return ba.x * ca.y - ca.x * ba.y;
}
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> pts[i].x;
    cin >> pts[i].y;
  }
  long long cnt = 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 (area(pts[i], pts[j], pts[k]) != 0) cnt += 1;
      }
  cout << cnt << endl;
}
