#include <bits/stdc++.h>
using namespace std;
short n, x[2003], y[2003];
int ans = 0;
int main() {
  scanf("%hd", &n);
  for (int i = 1; i <= n; ++i) scanf("%hd %hd", x + i, y + i);
  for (int i = 1; i < n - 1; ++i)
    for (int j = i + 1; j < n; ++j)
      for (int k = j + 1; k <= n; ++k)
        ans += !!(x[i] * (y[j] - y[k]) + x[j] * (y[k] - y[i]) +
                  x[k] * (y[i] - y[j]));
  printf("%d\n", ans);
}
