lightoj - 1294 - Positive Negative Sign

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main()
{
   int t,c;
   cin>>t;
   for(c=1;c<=t;c++)
   {
       ll n,m;
       cin>>n>>m;
       cout<< "Case "<<c<<": "<<n*m/2<<endl;

   }
}