///triang
#include <iostream>
#include <fstream>
#include <cmath>

using namespace std;

ifstream in ("triang.in");
ofstream out ("triang.out");

int N,cnt;

struct punct{
    double X;
    double Y;
}v[1502];

double distanta (punct a, punct b)
{
    return sqrt((a.X-b.X)*(a.X-b.X) + (a.Y-b.Y)*(a.Y-b.Y));
}

int main()
{
    in>>N;

    for (int i=1; i<=N; i++)    in>>v[i].X>>v[i].Y;

    for (int i=1; i<=N; i++)
        for (int j=i+1; j<=N; j++)
            for (int k=j+1; k<=N; k++)
            {
                if (abs(distanta(v[i],v[j])-distanta(v[i],v[k]))<0.001 && abs(distanta(v[i],v[j])-distanta(v[k],v[j]))<0.001)   cnt++;
            }


    out<<cnt;

    return 0;
}