uva-10790啦啦啦，居然做出來了，還真是需要點靈感呀

#include<iostream>
//#define ll long long
using namespace std;
long long n,m,t;
int main()
{
    while(cin>>n>>m&&n&&m)
    {
        long long ans=n*(n-1)*m*(m-1)/4;
        cout<<"Case "<<++t<<": "<<ans<<endl;
    }
}