#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
ifstream in("triang.in");
ofstream out("triang.out");
struct punct
{
    double x,y;
};
int main()
{
    double d1,d2,d3,aj1,aj2;
    short unsigned nrp,i,j,k;
    unsigned rez=0;
    in>>nrp;
    punct p[nrp+1];
    for(i=1;i<=nrp;i++) in>>p[i].x>>p[i].y;
    for(i=1;i<=nrp-2;i++)
        for(j=i+1;j<=nrp-1;j++)
            for(k=j+1;k<=nrp;k++)
            {
                aj1=p[i].x-p[j].x;
                aj2=p[i].y-p[j].y;
                d1=sqrt(aj1*aj2+aj2*aj2);
                aj1=p[j].x-p[k].x;
                aj2=p[j].y-p[k].y;
                d2=sqrt(aj1*aj2+aj2*aj2);
                aj1=p[i].x-p[k].x;
                aj2=p[i].y-p[k].y;
                d3=sqrt(aj1*aj2+aj2*aj2);
                if(d1==d2 && d2==d3) rez++;
            }
    out<<rez;
    in.close();
    out.close();
    return 0;
}