#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long long int a[n + 1], b[n + 1], val = 0ll;
  map<pair<double, double>, long long int> mp;
  map<pair<double, double>, long long int>::iterator it;
  map<double, long long int> cnt;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      double m = 100000007;
      double c = 0.0;
      if (a[i] == a[j]) {
        c = a[i];
      } else {
        m = (double)((1.0 * (b[i] - b[j])) / (a[i] - a[j]));
        c = b[i] - m * a[i];
      }
      mp[{m, c}]++;
    }
  }
  for (it = mp.begin(); it != mp.end(); it++) {
    double fs = (it->first).first;
    cnt[fs]++;
  }
  long long int sz = mp.size();
  for (it = mp.begin(); it != mp.end(); it++) {
    double fs = (it->first).first;
    val = val + (mp.size() - cnt[fs]);
  }
  cout << val / 2;
  return 0;
}
