#include<bits/stdc++.h>
using namespace std;
int n,x,y,ans;
set<pair<int,int> >sp; 
int main()
{
	cin>>n;
	for(int i=0;i<n;i++)
	{
		cin>>x>>y;
		sp.insert({x,y}); 
	}
	for(auto a:sp)
	{
		for(auto b:sp)
		{
			if(a.first!=b.first&&a.second!=b.second)
			{
				if(sp.find({a.first,b.second})!=sp.end()&&sp.find({b.first,a.second})!=sp.end())
				{
					ans++;
				}
			}
		}
	}
	cout<<ans/4;
	return 0;
}