#include <iostream>
#include <fstream>
#include <vector>
#include <set>
#include <algorithm>
#include <cmath>

using namespace std;

vector<pair<int,int>> el;
set<pair<int, int>> h;

int main() {

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

    int n, total = 0;
    double a, b;
    fin>>n;
    for(int i=0;i<n;i++){
        fin>>a>>b;
        el.emplace_back((int)round(a*10000), (int)round(b*10000));
        h.insert(el[i]);
    }
    fin.close();
    sort(el.begin(), el.end());
    for(int i=0;i<n;i++)
        for(int j=i+1;j<n;j++)
            if(el[j].first>el[i].first && el[j].second>el[i].second){
                int dx = el[j].first-el[i].first;
                int dy = el[j].second-el[i].second;
                if(h.find(make_pair(el[i].first-dy, el[i].second+dx))!=h.end() && h.find(make_pair(el[j].first-dy, el[j].second+dx))!=h.end())
                    total++;
            }
    fout<<total;
    fout.close();
    return 0;
}