#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  map<long double, long long> m1;
  set<pair<long double, long double>> m2;
  long long x[n + 1], y[n + 1];
  for (int i = int(1); i <= int(n); i++) cin >> x[i] >> y[i];
  for (int i = int(1); i <= int(n); i++) {
    for (int j = int(i + 1); j <= int(n); j++) {
      long double a = y[j] - y[i];
      long double b = x[i] - x[j];
      long double c = a * x[i] + b * y[i];
      pair<long double, long double> p;
      if (b == 0)
        p = make_pair(2000000000, c / a);
      else {
        a /= b;
        c /= b;
        a *= -1;
        p = make_pair(a, c);
      }
      if (m2.find(p) == m2.end()) {
        m1[p.first]++;
        m2.insert(p);
      }
    }
  }
  long long u = m2.size();
  long long ans = (u * (u - 1));
  ans /= 2;
  for (auto it : m1) {
    u = it.second;
    long long val = (u * (u - 1));
    val /= 2;
    ans -= val;
  }
  cout << ans;
}
