UVA_11723_Numbering_Road

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
#include <cctype>
#include <stack>
#include <queue>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <sstream>
#include <stdlib.h>
#include <cmath>
#define LL unsigned long long
using namespace std;

int main() {
     int n,r;
     int test=0;
    while(scanf("%d %d",&r,&n)){
        test++;
        if(n==0 && r==0) break;
        if(r<=n){
            printf("Case %d: 0\n",test);
        }else{
            if(27*n<r){
                printf("Case %d: impossible\n",test);
            }else{
             int d=r/n;
             if(r%n==0) d--;
                printf("Case %d: %d\n",test,d);
            }
        }

    }
    return 0;

}