#include <bits/stdc++.h>
using namespace std;
double dlina(int a, int b, int c, int d) {
  return sqrt((a - c) * (a - c) + (b - d) * (b - d));
}
long long powmod(long long a, long long n, long long m) {
  long long r = 1;
  for (; n; a = a * a % m, n >>= 1)
    if (n & 1) r = r * a % m;
  return r;
}
inline void read(long long &x) {
  char c = getchar();
  x = c - '0';
  c = getchar();
  while (c >= '0') {
    x = x * 10 + c - '0';
    c = getchar();
  }
}
inline void read(int &x) {
  char c = getchar();
  x = c - '0';
  c = getchar();
  while (c >= '0') {
    x = x * 10 + c - '0';
    c = getchar();
  }
}
void files() {
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
void fast_io() {
  ios_base::sync_with_stdio(false);
  cin.tie();
}
bool is_prime(int a) {
  for (int i = 2; i <= sqrt(a); i++)
    if (a % i == 0) return false;
  return true;
}
long long gcd(long long a, long long b) {
  if (!b) return a;
  return gcd(b, a % b);
}
long long cnt(long long n) {
  int res = 0;
  while (n) {
    n /= 10;
    res++;
  }
  return res;
}
pair<int, int> arr[2000];
void run() {
  int n;
  cin >> n;
  int ans = 0;
  for (int i = 0; i < n; i++) cin >> arr[i].first >> arr[i].second;
  for (int i = 0; i < n; i++)
    for (int j = i + 1; j < n; j++)
      for (int k = j + 1; k < n; k++)
        if ((arr[j].first - arr[i].first) * (arr[k].second - arr[i].second) ==
            (arr[j].second - arr[i].second) * (arr[k].first - arr[i].first))
          continue;
        else {
          ans++;
        }
  cout << ans;
}
int main() {
  fast_io();
  run();
  return 0;
}
