#include <fstream>
#include<cmath>
#include<algorithm>

#define eroare 0.0001
using namespace std;

ifstream f("patrate3.in");
ofstream g("patrate3.out");

int n, k;

struct coordonate
{
    double x,y;
}a, b ,v[1010];

bool compara(coordonate a, coordonate b)
{
    if(abs(a.x-b.x) < eroare)
        return a.y<b.y;
    return a.x<b.x;
}

bool cauta(coordonate a)
{
    int mij, st, dr;
    st=1, dr=n;
    while(st<=dr)
    {
        mij=(st+dr)/2;
        if(abs(v[mij].x-a.x)<eroare && abs(v[mij].y-a.y)<eroare)
            return true; /// am gasit punctul
        if(compara(v[mij],a))
            st=mij+1;
        else
            dr=mij-1;
    }
    return false;
}

int main()
{
    f>>n;
    for(int i=1;i<=n;i++)
        {
            f>>v[i].x>>v[i].y;
        }
        ///sortam crescator vectorul de puncte(dupa abscise, iar pt abscise egale dupa ordonate)
    sort(v+1,v+n+1,compara);

    for(int i=1 ; i<n ; i++)
        for(int j=i+1 ; j<=n ; j++)///punctele v[i] si v[j] formeaza o diagonala
        {   a.x=v[i].x+v[i].y-v[j].y;
            a.y=v[i].y+v[j].x-v[i].x;
            b.x=v[j].x+v[i].y-v[j].y;
            b.y=v[j].y+v[j].x-v[i].x;

            ///cautam binar cele 2 puncte aflate, iar daca sunt gasite inseamna ca formeaza un patrat cu cele 2 puncte alese initial
            if(cauta(a) && cauta(b))
                k++;
        }
    g<<k/2;
}