#include <bits/stdc++.h>
using namespace std;
int x[100001], y[100001], n;
long long ans = 0;
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%d%d", &x[i], &y[i]);
  bool notAligned;
  for (int i = 0; i < n; ++i) {
    for (int j = i + 1; j < n; ++j) {
      for (int k = j + 1; k < n; ++k) {
        notAligned = ((y[k] - y[i]) * (x[j] - x[i]) -
                      (x[k] - x[i]) * (y[j] - y[i])) != 0;
        ans += notAligned;
      }
    }
  }
  printf("%I64d\n", ans);
  return 0;
}
