#include <iostream>
#include <set>

#define pr pair<int, int>

using namespace std;


set<pr> stars;
set<pr> tested_vectors;
int sum = 0;

bool exist(pr star){
    return stars.find(star) != stars.end();
}

pr get_vector(pr a, pr b){
    a.first = b.first - a.first;
    a.second = b.second - a.second;
    return a;
//    if (x >= y)
}

pr sum_pairs(pr a, pr b){
    a.first = b.first + a.first;
    a.second = b.second + a.second;
    return a;
}

void test_vector(pr vec){
    for (auto it = stars.begin(); it != stars.end(); ++it){
        if (!exist(sum_pairs(*it, vec)) && !exist(get_vector(vec, *it))){
            return;
        }
    }
//    cout << vec.first << " " << vec.second << endl;
    sum += 2;
}

int main() {

    int n;
    cin >> n;

    for (int i = 0; i < n; ++i) {
        int a, b;
        cin >> a >> b;
        pr p;
        p.first = a; p.second = b;
        stars.insert(p);
    }

    pr vec;
    vec.first = 0; vec.second = 0;
    tested_vectors.insert(vec);

    for (auto it = stars.begin(); it != stars.end(); ++it){
        for (auto it2 = stars.begin(); it2 != stars.end(); ++it2){
            vec = get_vector(*it, *it2);
            if (tested_vectors.find(vec) == tested_vectors.end()){
//                cout << "test: "<< vec.first << " " << vec.second << endl;
                test_vector(vec);
                tested_vectors.insert(vec);
                vec.first *= -1;
                vec.second *= -1;
                tested_vectors.insert(vec);
            }
        }
    }

    std::cout << sum << std::endl;
    return 0;
}