#include <bits/stdc++.h>

using namespace std;

ifstream in("patrate3.in");
ofstream out("patrate3.out");
set<pair<int, int>> points;

bool check(pair<int, int> a, pair<int, int> b)
{
    if(a==b)
        return false;
    int dy=b.first-a.first, dx=a.second-b.second;
    return (points.find({a.first+dx, a.second+dy})!=points.end() && points.find({b.first+dx, b.second+dy})!=points.end());
}
int read_nr()
{
    double x;
    in>>x;
    return round(x*10000);
};

int main()
{
    int n;
    in>>n;
    while(n--)
        points.insert({read_nr(), read_nr()});
    int ans = 0;
    for(auto i : points)
        for(auto j : points)
            ans+=check(i, j);
    out<<ans/4<<'\n';
    return 0;
}