10790 - How Many Points of Intersection?

#include <cstdio>
#include <iostream>
using namespace std;

int
main ( int argc, char *argv[] )
{
freopen("data","r",stdin);
long long int a,b;
int Case = 1;
while(scanf("%lld %lld",&a,&b)){
if(a+b == 0)
{
break;
}
cout<<"Case "<<Case++<<": ";
cout<<((a-1)*a*(b-1)*b)/4<<endl;
}

return 0;
}                /* ----------  end of function main  ---------- */