#include<iostream>
using namespace std;
#define ll long long
ll n, m;
ll t;
int main(){
    while (cin >> n >> m){
        //特判n=2
        cout << "Case #" << ++t << ": ";
        if (n == 2){
            cout << (m % 2?1:2) << endl;
        }
        else if (n >= m){
            cout << m << endl;
        }
        else{
            m -= n;
            ll d = m / (n - 1);
            ll k = m % (n - 1);
            if (k !=0)cout << k << endl;
            else{
                if (d % 2 == 0)cout << n  << endl;
                else cout << n-1 << endl;
            }
            
        }
    }
    
}