#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
 
const int N=1010;
const int H=10007;
int ptx[N], pty[N];
 
struct Node
{
	int x;
	int y;
	int next;
};
Node node[N];
int cur;
int n;
long ans;
int hashTable[H];
 
void initHash()
{
	for(int i=0;i<H;++i)
		hashTable[i]=-1;
	cur=0;
	ans=0;
}
 
void insertHash(int x, int y)
{
	int h=(x*x+y*y)%H;
	node[cur].x=x;
	node[cur].y=y;
	node[cur].next=hashTable[h];
	hashTable[h]=cur;
	++cur;
}
 
bool searchHash(int x,int y)
{
	int h=(x*x+y*y)%H;
	int next;
	next=hashTable[h];
	while(next!=-1)
	{
		if(x==node[next].x&&y==node[next].y)
			return true;
		next=node[next].next;
	}
	return false;
}
 
int main()
{
	while(scanf("%d",&n)!=EOF&&n)
	{
		initHash();
		for(int i=0;i<n;++i) 
		{
			scanf("%d%d",&ptx[i],&pty[i]);
			insertHash(ptx[i],pty[i]);
		}
		for(int i=0;i<n;++i)
		{
			for(int j=i+1;j<n;++j)
			{
				int x1=ptx[i]-(pty[i]-pty[j]);
				int y1=pty[i]+(ptx[i]-ptx[j]);
				int x2=ptx[j]-(pty[i]-pty[j]);
				int y2=pty[j]+(ptx[i]-ptx[j]);
				if(searchHash(x1,y1)&&searchHash(x2,y2))
					++ans;
			}
		}
		for(int i=0;i<n;++i)
		{
			for(int j=i+1;j<n;++j)
			{
				int x1=ptx[i]+(pty[i]-pty[j]);
				int y1=pty[i]-(ptx[i]-ptx[j]);
				int x2=ptx[j]+(pty[i]-pty[j]);
				int y2=pty[j]-(ptx[i]-ptx[j]);
				if(searchHash(x1, y1)&&searchHash(x2, y2))
					++ans;
			}
		}
		ans>>=2;
		printf("%ld\n", ans);
	}
	return 0;
}