#include<bits/stdc++.h>
using namespace std;
ifstream f("patrate3.in");
ofstream g("patrate3.out");
#define x first
#define y second
#define P pair<double,double>
const double E=0.0001;
int n,i,j,c;
P v[1<<10],a,b;
double x,y;
bool C(P a,P b)
{
    return a.x<=b.x-E||(a.x<b.x+E&&a.y<=b.y-E);
}
int main()
{
    for(f>>n,i=1;i<=n;++i)
        f>>v[i].x>>v[i].y;
    for(sort(v+1,v+1+n),i=1;i<=n;++i)
        for(j=i+1;j<=n;++j)
            if(v[j].x>v[i].x&&v[j].y>=v[i].y)
                x=v[j].x-v[i].x,y=v[j].y-v[i].y,a={v[i].x-y,v[i].y+x},b={v[j].x-y,v[j].y+x},c+=(binary_search(v+1,v+1+n,b,C)&&binary_search(v+1,v+1+n,a,C));
    g<<c;
    return 0;
}