#include <bits/stdc++.h>

using namespace std;

ifstream fin("patrate3.in");
ofstream fout("patrate3.out");

set<pair<int,int>> h; //set, ca sa nu se repete punctele, la unordered map s-ar fi putur repeta abscisa
pair<int,int> v[1001];

bool patrat(pair<int,int> a, pair<int,int> b)
{
    int x, y;
    //verificam daca sunt egale coordonatele celorlalte 2 puncte
    x = a.second - b.second;
    y = b.first - a.first;

    pair<int,int> aux1,aux2;

    aux1.first = a.first + x;
    aux1.second = a.second + y;

    aux2.first = b.first + x;
    aux2.second = b.second + y;

    if(h.find(aux1) != h.end() && h.find(aux2) != h.end())
        return 1;

    return 0;
}

int main()
{
    int n, c = 0;
    double x,y;

    fin>>n;

    for(int i = 1; i <= n; i++)
    {
        fin>>x>>y;
        v[i].first = round(x * 10000);
        v[i].second = round(y * 10000);

        h.insert(v[i]);
    }

    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= n; j++)
            if(i != j && patrat(v[i],v[j]))
                    c++;

    fout<<c/4; //patratul este numarat pt fiecare varf al sau, deci impartim la 4

    return 0;
}