#include <bits/stdc++.h>
using namespace std;
int x[2001], y[2001], n, ans, ai, k;
int anchor, pend[2001], ps;
inline int cP(int a, int b, int c) {
  return x[a] * (y[b] - y[c]) + y[a] * (x[c] - x[b]) + x[b] * y[c] -
         x[c] * y[b];
}
bool lexicalLess(int a, int b) {
  if (x[a] == x[b]) return y[a] < y[b];
  return x[a] < x[b];
}
bool grahamLess(int a, int b) {
  int val = cP(anchor, a, b);
  if (val != 0) return val > 0;
  return lexicalLess(a, b);
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d %d", x + i, y + i);
    pend[ps++] = i;
  }
  while (ps > 3) {
    anchor = pend[0];
    ai = 0;
    for (int i = 1; i < ps; i++)
      if (lexicalLess(pend[i], anchor)) {
        anchor = pend[i];
        ai = i;
      }
    swap(pend[ai], pend[--ps]);
    sort(pend, pend + ps, grahamLess);
    for (int i = 0; i < ps; i++) {
      k = 0;
      while (i + k + 1 < ps && cP(anchor, pend[i], pend[i + k + 1]) == 0) k++;
      ans -= k * (k + 1) / 2;
      i += k;
    }
    ans += ps * (ps - 1) / 2;
  }
  if (cP(pend[0], pend[1], pend[2]) != 0) ans++;
  printf("%d\n", ans);
}
