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

set<pair<int, int>> s;

int main() {
    ifstream f("patrate3.in");
    ofstream g("patrate3.out");

    int n; f >> n;
    for(int i=1; i<=n; i++) {
        float x, y; f >> x >> y;
        x = round(x * 10000);
        y = round(y * 10000);
        s.emplace(int(x), int(y));
    }

    int ans = 0;
    for(auto i : s)
        for(auto j : s) {
            if(i == j) continue;

            int dx = i.second - j.second;
            int dy = j.first - i.first;
            pair<int, int> p1 = {dx + i.first, dy + i.second};
            pair<int, int> p2 = {dx + j.first, dy + j.second};
            if(s.find(p1) != s.end() and s.find(p2) != s.end()) ans++;
        }
    g << ans / 4;
    return 0;
}