/*#include<stdio.h>
#include<math.h>
#define N 15001
const double eps=1e-3;
int num,n;
struct milk{double x,y;}v[N];
void parcurg()
{
	for (int i=1; i<n-1; ++i)
	{
		for (int j=i+1; j<n; ++j)
			{
			double ab=(v[i].x-v[j].x)*(v[i].x-v[j].x)+(v[i].y-v[j].y)*(v[i].y-v[j].y);
			//int ab1=ab;
			for (int k=j+1; k<=n; ++k)
				{
				double ac=(v[i].x-v[k].x)*(v[i].x-v[k].x)+(v[i].y-v[k].y)*(v[i].y-v[k].y);
				//int ac1=ac;
				double bc=(v[k].x-v[j].x)*(v[k].x-v[j].x)+(v[k].y-v[j].y)*(v[k].y-v[j].y);
				//int bc1=bc;
				if (ab+eps==bc&& bc+eps==ac)
					++num;
				}
			}
	}
	printf("%d",num);
}
void citire()
{
	freopen("triang.in","r",stdin);
	freopen("triang.out","w",stdout);
	scanf("%d",&n);
	for (int i=1; i<=n; ++i)
		scanf("%lf%lf",&v[i].x,&v[i].y);
	parcurg();
}
int main()
{
	citire();
	return 0;
}*/
#include<cstdio>
#include<algorithm>
#define N 15001
#define M 2000
//#define M 37507501
using namespace std;
const double eps=1e-3;
struct triang{double x,y;}v[N];
short int n;
int num;
double a[M];
bool compar(const double &a,const double&b)
{
	return a+eps<b;
}
void citire()
{
	freopen("triang.in","r",stdin);
	freopen("triang.out","w",stdout);
	scanf("%hd",&n);
	for (short int i=1; i<=n; ++i)
	{
		scanf("%lf",&v[i].x);
		scanf("%lf",&v[i].y);
		for (short int j=1; j<i; ++j)
			a[++num]=(v[i].x-v[j].x)*(v[i].x-v[j].x)+(v[i].y-v[j].y)*(v[i].y-v[j].y);
	}
}
void numar()
{
	int nr=1,rez=0;
	for (int i=1; i<num; ++i)
		if (a[i+1]+eps>=a[i])
			++nr;
		else
		{
			rez+=nr*(nr-1)*(nr-2)/6;
			nr=1;
		}
	rez+=nr*(nr-1)*(nr-2)/6;
	printf("%d",rez);
}
int main()
{
	citire();
	sort (a+1,a+1+num,compar);
	numar();
	return 0;
}