#include <bits/stdc++.h>
using namespace std;
int main(int argc, char *argv[]) {
  int n;
  cin >> n;
  int x[2000], y[2000];
  for (int i = 0; i < n; i++) cin >> x[i] >> y[i];
  long long sum = 0;
  for (int i = 0; i < n - 2; i++)
    for (int j = i + 1; j < n - 1; j++)
      for (int k = j + 1; k < n; k++)
        if ((x[j] - x[i]) * (y[k] - y[i]) - (y[j] - y[i]) * (x[k] - x[i]))
          sum++;
  cout << sum << endl;
  return 0;
}
