#include <iostream>
#include <vector>
#include <algorithm>
#include <map>

using namespace std;

int main()
{
	int t;
	cin >> t;

	for( int tc = 0; tc < t; tc++)
	{
		int n;
		cin >> n;
		int i, j;
		vector<pair<int,int> > pairs(n);
		for( i = 0; i < n; i++ )
		{
			int x,y;
			cin >> x >> y;
			pairs[i] = make_pair(x,y);
		}
		long long res = 0;
		map<int, int> dmap;
		for( i = 0; i < n; i++ )
		{
			dmap.clear();
			for( j = 0; j < n; j++ )
			{
				if( i != j )
				{
					int d = (pairs[i].first-pairs[j].first)*(pairs[i].first-pairs[j].first) + 
							(pairs[i].second-pairs[j].second)*(pairs[i].second-pairs[j].second);
					res += dmap[d];
					dmap[d]++;
				}
			}
		}		

		cout << "Case #" << (tc+1) << ": " << res<< endl;
	}
	return 0;
}