#include<bits/stdc++.h>

using namespace std;
ifstream f("patrate3.in");
ofstream g("patrate3.out");
int n,sol;
struct pct
{
    int x,y;
} a[1005];
bool comp(pct X,pct Y)
{
    if(X.x==Y.x)
        return X.y<Y.y;
    return X.x<Y.x;
}
bool cautare(pct r)
{
    int X=r.x;
    int Y=r.y;
    int st=1,dr=n;
    while(st<=dr)
    {
        int mj=(st+dr)/2;
        if(a[mj].x<X)
            st=mj+1;
        else if(a[mj].x>X)
            dr=mj-1;
        else if(a[mj].x==X)
        {
            if(a[mj].y<=Y)
                st=mj+1;
            else
                dr=mj-1;
        }
    }
    if(a[st-1].x==X&&a[st-1].y==Y)
        return true;
    return false;
}
int main()
{
    f>>n;
    for(int i=1; i<=n; i++)
    {
        double X,Y;
        f>>X>>Y;
        a[i].x=round(X*10000);
        a[i].y=round(Y*10000);
    }
    sort(a+1,a+n+1,comp);
    for(int i=1; i<n; i++)
        for(int j=i+1; j<=n; j++)
            if(a[i].x<a[j].x&&a[i].y<=a[j].y)
            {
                pct x1;
                x1.x=a[i].x-(a[j].y-a[i].y);
                x1.y=a[i].y+(a[j].x-a[i].x);
                pct x2;
                x2.x=a[j].x-(a[j].y-a[i].y);
                x2.y=a[j].y+(a[j].x-a[i].x);
                if(cautare(x1)&&cautare(x2))
                    sol++;
            }
    g<<sol;
    return 0;
}