#include<iostream>
using namespace std;
 int main(){
int a;
cin >>a;
    for (int i = 1; i <= a; i++) { //做a次
        int b,c;
        cin >>b>>c;
        if(b%2 == 0){              //是否是偶數
            b+=1;
        }
        if(c % 2 == 0){
            c-=1;
        }
        int n=(c-b)/2+1;
        int d;
        d=(b+c)/2*n;
        cout << "Case " << i << ": ";
        cout << (b + c) / 2 * ((c - b) / 2 + 1) << '\n';
    }
}