#include <bits/stdc++.h>
using namespace std;
int N;
int points[2005][2] = {0}, cnp = 1;
int main() {
  scanf("%d", &N);
  for (int i = 1; i <= N; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    points[i][0] = x;
    points[i][1] = y;
  }
  int ans = 0;
  for (int i = 1; i <= N; i++) {
    for (int j = i + 1; j <= N; j++) {
      for (int k = j + 1; k <= N; k++) {
        if ((points[j][0] - points[i][0]) * (points[k][1] - points[i][1]) ==
            (points[k][0] - points[i][0]) * (points[j][1] - points[i][1]))
          continue;
        ans++;
      }
    }
  }
  printf("%d", ans);
  return 0;
}
