#include<bits/stdc++.h>

using namespace std;

int n;

int vis[][];

struct point

{

    int x,y;

    bool operator<(const point& rhs)const

    {

        return x<rhs.x || x==rhs.x&&y<rhs.y;

    }

}p[];

int main()

{

    while(~scanf("%d",&n))

    {

        memset(vis,,sizeof(vis));

        int ans=;

        for(int i=;i<n;i++)

        {

            scanf("%d%d",&p[i].x,&p[i].y);

            p[i].x+=,p[i].y+=;

            vis[p[i].x][p[i].y]=;

        }

        sort(p,p+n);

        for(int i=;i<n;i++)

            for(int j=i+;j<n;j++)

            {

                point a=p[i],b=p[j];

                int dx=b.x-a.x;

                int dy=b.y-a.y;

                point c,d;

                c.x=a.x-dy,c.y=a.y+dx;

                d.x=b.x-dy,d.y=b.y+dx;

                if(vis[c.x][c.y]&&vis[d.x][d.y]) ans++;

            }

        printf("%d\n",ans/);

    }

}