#include <bits/stdc++.h>
using namespace std;
map<double, int> cnt;
double xx[20005];
double yy[20005];
int n;
long long _minus = 0;
long long ans;
double loz = 0x3f3f3f;
double k(int id1, int id2) {
  if (xx[id1] == xx[id2]) return loz;
  return (yy[id1] - yy[id2]) / (xx[id1] - xx[id2]);
}
void calc(int x) {
  cnt.clear();
  vector<double> luu;
  for (int i = 1; i <= n; i++) {
    if (i == x) continue;
    double tmp = k(i, x);
    if (cnt[tmp] == 0) luu.push_back(tmp);
    cnt[tmp]++;
  }
  for (int i = 0; i < luu.size(); i++) {
    int tmp = cnt[luu[i]];
    if (tmp < 2) continue;
    _minus += 1ll * tmp * (tmp - 1) / 2;
  }
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    int x, y;
    scanf("%lf %lf", &xx[i], &yy[i]);
  }
  if (n < 3) {
    cout << "0";
    return 0;
  }
  ans = 1ll * n * (n - 1) * (n - 2) / 6;
  for (int i = 1; i <= n; i++) {
    calc(i);
  }
  _minus /= 3;
  ans -= _minus;
  printf("%lld", ans);
}
