#include <bits/stdc++.h>

using namespace std;

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

const double EPS=1e-5,c=0.5,s=sqrt(3)/2;

struct Punct
{
    double x,y;
    Punct (double xx=0.0,double yy=0.0)
    {
        x=xx;
        y=yy;
    }
    bool operator <(const Punct &A) const
    {
        if(abs(x-A.x)>EPS)
            return x<A.x;
        if(abs(y-A.y)>EPS)
            return y<A.y;
        return 0;
    }
};

set <Punct> S;

Punct rotire(const Punct &A,const Punct &B)
{
    double dx=B.x-A.x,dy=B.y-A.y;
    return Punct(dx*c-dy*s+A.x,dx*s+dy*c+A.y);
}

int main()
{
    int N,nrTr=0;
    Punct A,M;
    f>>N;
    while(N--)
    {
        f>>A.x>>A.y;
        for(auto &B:S)
        {
            M=rotire(A,B);
            if(S.find(M)!=S.end())
                nrTr++;
        }
        S.insert(A);
    }
    g<<nrTr;
    return 0;
}