#include<cstdio>

 #include<iostream>

 using namespace std;

 inline int check(int x){

     int ans = ;

     while(x){

         ans += x / ;

         x /= ;

     }

     return ans;

 }//处理5的个数，即末尾0的个数 

 int main(){

     int t, m = ;

     scanf("%d", &t);

     while(t--){

         int ans = , a;

         m++;

         scanf("%d", &a);

         int l = , r = 5e8 + ;

         while(l <= r){

             int mid = (l + r) >> ;

             int _mid = check(mid);

             if(_mid > a) r = mid - ;

             else if(_mid < a) l = mid + ;

             else if(_mid == a) {ans = mid; r = mid - ;}//可能有答案遗漏

         }

         if(ans) printf("Case %d: %d\n", m, ans);

         else printf("Case %d: impossible\n", m);

     }

     return ;

 }