#include <bits/stdc++.h>
// #include <atcoder/modint>
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define INF 2000000000000000000
#define ll long long
#define ull unsigned long long
#define ld long double
#define pll pair<ll, ll>
using namespace std;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const double PI = 3.141592653589793238462643383279;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll N;
  cin >> N;
  vector<ll> X(N), Y(N);
  for (ll i = 0; i < N; ++i) {
    cin >> X.at(i) >> Y.at(i);

  }
  //y = ax + b
  //gradient = a = dy / dx
  //{dx, dy}
  vector<vector<pll>> gradient(N);
  for (ll i = 0; i < N; ++i) {
    for (ll j = 0; j < N; ++j) {
      if (i == j) {
        continue;
      }
      ll dx = X.at(i) - X.at(j), dy = Y.at(i) - Y.at(j);
      if (dx == 0) {
        if (dy >= 0) {
          gradient.at(i).push_back({INF, 0});
        }
        else {
          gradient.at(i).push_back({-INF, 0});
        }
      }
      else {
        // if (dx < 0) {
        //   dx = -dx;
        //   dy = -dy;
        // }
        ll gcd = abs(__gcd(dx, dy));
        gradient.at(i).push_back({dx / gcd, dy / gcd});
      }
    }
  }
  ll ans = 0;
  for (ll i = 0; i < N; ++i) {
    sort(rng(gradient.at(i)));
    // cout << "i" << i << "\n";
    // for (ll j = 0; j < gradient.at(i).size(); ++j) {
    //   cout << gradient.at(i).at(j).first << " " << gradient.at(i).at(j).second << "\n";
    // }
    // cout << "\n";
    for (ll j = 0; j < (ll)gradient.at(i).size() - 1; ++j) {
      if (gradient.at(i).at(j) == gradient.at(i).at(j + 1)) {
        ans += 1;
        break;
      }
    }
  }
  cout << ans << "\n";
}