#include <bits/stdc++.h>
#define FOR(a, b, c) for(int a = b; a < c; ++a)
#define MP make_pair
#define PB push_back

using namespace std;

typedef long long LL;

vector <pair <int, int> > points;

bool check(int x, int y)
{
    set <pair <int, int> > stars;
    for(auto& i : points){
        stars.insert(i);
    }

    for(auto& i : points)
    {
        if(!stars.count(MP(i.first + x, i.second + y)) && !stars.count(MP(i.first - x, i.second - y)))
            return false;
    }

    return true;
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n;
    cin >> n;

    if(n == 0 || n == 1)
    {
        cout << 0;
        return 0;
    }

    FOR(i, 0, n)
    {
        int a, b;
        cin >> a >> b;

        points.PB(MP(a, b));
    }

    int res = 0;

    FOR(i, 1, n)
    {
        if(points[i].first == points[0].first && points[i].second == points[0].second) continue;
        if(check(points[i].first - points[0].first, points[i].second - points[0].second))
            res += 2;
    }

    cout << res;

    return 0;
}