#include <iostream>
#include <fstream>
#include <set>
#include <math.h>
#include <utility>

int main()
{
    std::ifstream f("patrate3.in");
    std::ofstream g("patrate3.out");
    std::set<std::pair<int, int>> Hash_Puncte;
    short N;
    int Rezultat = 0;
    f >> N;

    for(float px, py, i = 0; i < N; ++i)
    {
        f >> px >> py;
        Hash_Puncte.insert(std::make_pair(round(px * 10000), round(py * 10000)));
    }
    for(auto it1 = Hash_Puncte.begin(); it1 != Hash_Puncte.end(); ++it1)
        for(auto it2 = Hash_Puncte.begin(); it2 != Hash_Puncte.end(); ++it2)
            if(it1 != it2)
            {
                float px3 = it1->second - it2->second + it2->first;
                float px4 = it1->second - it2->second + it1->first;
                float py3 = it2->first - it1->first + it2->second;
                float py4 = it2->first - it1->first + it1->second;

                if(Hash_Puncte.find(std::make_pair(px3, py3)) != Hash_Puncte.end() &&
                   Hash_Puncte.find(std::make_pair(px4, py4)) != Hash_Puncte.end())
                    ++Rezultat;
            }
    g << Rezultat / 4;

    return 0;
}