uva 10790

#include<stdio.h>

int main()
{
    long long m , n;
    int  t = 1 ;
    while(scanf("%lld%lld",&m,&n) && m && n)
    {
        printf("Case %d: %lld
",t , m*n*(m-1)*(n-1)/4) ;
        t++;
    }
    return 0 ;
}

参考：http://cnblogs.com/xiaocai905767378/archive/2011/04/27/2030213.html