#include <bits/stdc++.h>
using namespace std;
int n, ans = 0;
vector<pair<int, int> > arr;
int sqr(int a) { return a * a; }
int main(int argc, char *argv[]) {
  scanf("%d", &n);
  arr.resize(n);
  for (int i = 0; i < n; ++i) {
    scanf("%d%d", &arr[i].first, &arr[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) {
        int s = abs(
            (arr[i].first + arr[j].first) * (arr[i].second - arr[j].second) +
            (arr[j].first + arr[k].first) * (arr[j].second - arr[k].second) +
            (arr[k].first + arr[i].first) * (arr[k].second - arr[i].second));
        if (s) {
          ++ans;
        }
      }
    }
  }
  printf("%d", ans);
  return 0;
}
