#include <bits/stdc++.h>
using namespace std;
int a1[2000][2];
map<double, int> mp;
int main() {
  int n, a;
  long long o;
  double d;
  scanf("%d", &n);
  o = (long long)n * (n - 1) * (n - 2) / 2;
  for (int i = 0; i < n; ++i) scanf("%d%d", a1[i], a1[i] + 1);
  for (int i = 0; i < n; ++i) {
    mp.clear();
    a = 0;
    for (int j = 0; j < n; ++j)
      if (i != j) {
        if (a1[i][1] == a1[j][1]) {
          o -= a;
          ++a;
          continue;
        }
        d = (double)(a1[i][0] - a1[j][0]) / (a1[i][1] - a1[j][1]);
        if (d == 0) d = 0;
        o -= mp[d];
        ++mp[d];
      }
  }
  printf("%I64d\n", o / 3);
}
