#include <bits/stdc++.h>
int main() {
  int vertices;
  std::cin >> vertices;
  int x[vertices], y[vertices];
  for (int i = 0; i < vertices; i++) {
    std::cin >> x[i] >> y[i];
  }
  int ways = 0;
  for (int i = 0; i < vertices; i++) {
    for (int j = i + 1; j < vertices; j++) {
      for (int k = j + 1; k < vertices; k++) {
        if ((x[i] * y[j] + x[j] * y[k] + x[k] * y[i]) -
            (x[j] * y[i] + x[k] * y[j] + x[i] * y[k])) {
          ways++;
        }
      }
    }
  }
  std::cout << ways;
  return 0;
}
