#include <bits/stdc++.h>
using namespace std;
int dx[] = {+1, -1, 0, 0};
int dy[] = {0, 0, +1, -1};
int dx2[] = {+1, -1, 0, 0, +1, +1, -1, -1};
int dy2[] = {0, 0, +1, -1, +1, -1, -1, +1};
long long squ(long long x) { return (x * x); }
long long power(long long n, long long k) {
  long long N = n;
  for (long long i = 2; i <= k; i++) N *= n;
  return N;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int n, i, j, k, ans = 0;
  pair<int, int> x[2005];
  cin >> n;
  for (i = 0; i < n; i++) cin >> x[i].first >> x[i].second;
  for (i = 0; i < n - 2; i++) {
    for (j = i + 1; j < n - 1; j++) {
      for (k = j + 1; k < n; k++) {
        if ((x[k].first - x[j].first) * (x[j].second - x[i].second) ==
            (x[j].first - x[i].first) * (x[k].second - x[j].second))
          continue;
        ans++;
      }
    }
  }
  cout << ans;
  return 0;
}
