#include<iostream.h>
#include<fstream.h>
#include<math.h>
int n,nr;
struct data{
	double x,y;
	};
typedef struct data dt;
dt a[1000];
void citire(){
	ifstream fin("patrate.in");
	fin>>n;
	for(int i=0;i<n;i++)
		fin>>a[i].x>>a[i].y;
	fin.close();
}
int lungime(dt c,dt d){
	return sqrt((c.x-d.x)*(c.x-d.x)+(c.y-d.y)*(c.y-d.y));
	}
int numarare(){
	for(int i=0;i<n;i++)
	 for(int j=i+1;j<n;j++)
	  for(int k=j+1;k<n;k++)
	   for(int l=k+1;k<n;k++)
	    if(lungime(a[i],a[j])==lungime(a[k],a[l]))
	     if((lungime(a[i],a[k])==lungime(a[j],a[l]))||(lungime(a[i],a[l])==lungime(a[j],a[k])))
		nr++;
	  }
void main(){
	ofstream fout("patrate.out");
	citire();
	fout<<numarare()/4;
	fout.close();
	}