#include <bits/stdc++.h>
#define PDD pair<double,double>
#define X first
#define Y second

using namespace std;

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

int n,tot;
PDD a[1501];

double Dist(PDD a,PDD 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>>a[i].X>>a[i].Y;

    sort(a+1,a+1+n);

    for(int i=1;i<=n-2;i++)
        for(int j=i+1;j<=n-1;j++)
        {
            double dist=Dist(a[i],a[j]);
            int poz=j;

            for(int p=n;p;p/=2)
                while(poz+p<=n && fabs(Dist(a[j],a[poz+p])-dist)>0.0001)
                    poz+=p;
            poz++;

            while(poz<=n && fabs(Dist(a[j],a[poz])-dist)<0.0001)
            {
                if(fabs(Dist(a[i],a[poz])-dist)<0.0001)
                    tot++;
                poz++;
            }
        }

    out<<tot;

    return 0;
}