#include <bits/stdc++.h>
using namespace std;
vector<double> s;
vector<pair<int, int> > a;
int x, y;
double k;
long long n, ans, sum;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%d%d", &x, &y);
    a.push_back(make_pair(x, y));
  }
  ans = n * (n - 1) * (n - 2) / 6;
  for (int i = 0; i < a.size(); ++i) {
    s.clear();
    for (int j = i + 1; j < a.size(); ++j) {
      if (a[i].second == a[j].second)
        k = 0;
      else if (a[i].first == a[j].first)
        k = 1000000000;
      else
        k = (a[i].first - a[j].first) * 1.0 / (a[i].second - a[j].second);
      s.push_back(k);
    }
    sort(s.begin(), s.end());
    sum = 1;
    for (int j = 1; j < s.size(); ++j)
      if (abs(s[j - 1] - s[j]) <= 1e-9)
        ++sum;
      else {
        ans -= sum * (sum - 1) / 2;
        sum = 1;
      }
    ans -= sum * (sum - 1) / 2;
  }
  cout << ans << "\n";
  return 0;
}
