#include <iostream>
#include <unordered_map>
#include <unordered_set>
#include <fstream>
#include <algorithm>


using namespace std;

unordered_map<double,int> unmap;
unordered_set<double> unset;
struct punct{
    double x;
    double y;
};
punct v[1001],p;
int contor=0;

int main()
{
    int n,i;
    ifstream f("patrate3.in");
    ofstream g("patrate3.out");
    f>>n;
    double xx,yy;
    for(i=1;i<=n;i++){
        f>>xx>>yy;
        p.x=xx;
        p.y=yy;
        v[i]=p;

        unmap.insert(make_pair<double&,int&>(xx,i));
        unmap.insert(make_pair<double&,int&>(yy,i));
    }

    //sort(v+1);
    //sort(v+n+1);
    //cout<<(unmap.find(2.5212)!=unmap.end());
    int j;
    punct a,b,c,d;
    for(i=1;i<=n;i++){
        for(j=1;j<=n;j++){
            if(i!=j){
            a=v[i];
            b=v[j];
            c.x=a.x+(a.y-b.y);
            c.y=a.y+(b.x-a.x);

            d.x=b.x+(a.y-b.y);
            d.y=b.y+(b.x-a.x);

  //          cout<<i<<" cu "<<j<<" face C("<<c.x<<", "<<c.y<<") si D("<<d.x<<", "<<d.y<<")"<<'\n';
            int ic,id;
            unordered_map<double,int>::const_iterator got = unmap.find (c.x);
            if ( got != unmap.end() )
                ic=got->second;
            //std::cout << got->first << " is " << got->second;
//cout<<endl;
            got=unmap.find(c.y);
            if ( got != unmap.end() )
                if(ic==got->second){
  //                  cout<<"c gasit"<<ic<<" cu "<<a.x<<","<<a.y<<" si"<<b.x<<","<<b.y<<" hai si d care e"<<d.x;
                    contor++;
                }
//cout<<endl;
    //        cout<<(unmap.find(d.x)!=unmap.end())<<"M"<<d.x;
            got=unmap.find(d.x);
            if ( got != unmap.end() )
                id=got->second;
  //          cout<<id;
//cout<<endl;
            got=unmap.find(d.y);
            if ( got != unmap.end() )
                if(id==got->second){
        //            cout<<"d gasit"<<id<<" cu "<<a.x<<","<<a.y<<" si"<<b.x<<","<<b.y<<" hai si c care e"<<c.x;
                    contor++;
                }

            //cout<<(unmap.find(c.y)!=unmap.end());
            }
        }
      //  cout<<endl;
    }
    g<<contor;
    return 0;
}