#include <bits/stdc++.h>
using namespace std;
using ll = long long;

template<class T> istream& operator >> (istream& is, vector<T>& vec) {
    for(T& x : vec) is >> x;
    return is;
}

template<class T> ostream& operator << (ostream& os, const vector<T>& vec) {
    if(vec.empty()) return os;
    os << vec[0];
    for(auto it = vec.begin(); ++it != vec.end(); ) os << ' ' << *it;
    return os;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<pair<ll,ll>> a(n);
    ll x, y, x2, y2;
    for(int i = 0; i < n; i++){
        cin >> x >> y;
        a[i] = {x, y};
    }

    vector<bool> used(n);
    for(int i = 0; i < n; i++){
        vector<pair<ll,ll>> b(n);
        for(int j = 0; j < n; j++){
            b[j].first = a[j].first - a[i].first;
            b[j].second = a[j].second - a[i].second;
            ll g = __gcd(b[j].first, b[j].second);
            g = abs(g);
            if(g >= 1){
                b[j].first /= g;
                b[j].second /= g;
            }
        }
        auto c = b;
        sort(c.begin(), c.end());
        for(int j = 0; j < n; j++){
            ll x, y;
            tie(x, y) = b[j];
            if(j == i) continue;
            x *= -1, y *= -1;
            if(binary_search(c.begin(), c.end(), make_pair(x, y))){
                used[j] = true;
            }
        }
    }
    cout << count(used.begin(), used.end(), true) << '\n';
}