#include <bits/stdc++.h>
using namespace std;
bool Check(pair<int, int> firstP, pair<int, int> secondP,
           pair<int, int> thirdP) {
  return (firstP.first * secondP.second + firstP.second * thirdP.first +
          secondP.first * thirdP.second) -
         (thirdP.first * secondP.second + thirdP.second * firstP.first +
          secondP.first * firstP.second);
}
int main() {
  int n;
  unsigned long long counter = 0;
  cin >> n;
  pair<int, int> Points[n];
  for (int i = 0; i < n; i++) cin >> Points[i].first >> Points[i].second;
  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      for (int k = j + 1; k < n; k++) {
        if (Check(Points[i], Points[j], Points[k])) counter++;
      }
    }
  }
  cout << counter;
  return 0;
}
