#include <bits/stdc++.h>
using namespace std;
double x[(int)2e3 + 10], y[(int)2e3 + 10];
long long nCr(long long n, long long r) {
  if (r > n) return 0;
  if (n == r) return 1;
  return nCr(n - 1, r) * n / (n - r);
}
int main() {
  long long n;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> x[i] >> y[i];
  }
  if (n < 3) return cout << 0 << endl, 0;
  long long ans = nCr(n, 3);
  for (int i = 0; i < n; ++i) {
    map<double, int> m;
    for (int j = i + 1; j < n; ++j) {
      if (x[i] == x[j])
        m[1e9]++;
      else if (y[i] > y[j])
        m[(y[i] - y[j]) / (x[i] - x[j])]++;
      else
        m[(y[j] - y[i]) / (x[j] - x[i])]++;
    }
    map<double, int>::iterator it;
    for (it = m.begin(); it != m.end(); ++it) {
      ans -= nCr(it->second, 2);
    }
  }
  cout << ans << endl;
  return 0;
}
