#include <bits/stdc++.h>

using namespace std;

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

set <pair<int, int>> M;

int main()
{
    int n, cnt = 0;
    fin >> n;
    for (int i = 1; i <= n; i++)
    {
        double x , y;
        fin >> x >> y;
        int int_x = x * 10000;
        int int_y = y * 10000;
        M.insert({int_x, int_y});
    }
    for (auto i = M.begin(); i != M.end (); i++)
        for (auto j = M.begin(); j != M.end (); j++)
        {
            if (i != j)
            {
                pair <int,int> C, D;
                C = D = {0 , 0};
                C.first = i -> first + (i -> second - j -> second);
                C.second = i -> second + (j -> first - i -> first);
                D.first = j -> first + (i -> second - j -> second);
                D.second = j -> second + (j -> first - i -> first);
                if (M.find (C) != M.end () && M.find (D) != M.end ())
                    cnt++;

            }
        }
    fout << cnt / 4 << "\n";
    return 0;
}