#include<bits/stdc++.h>
using namespace std;

long long int check(long long int mid)
{
    long long int cnt=0,n=mid;
    for(int j=5; n/j>=1; j*=5)
    {
        cnt+=(n/j);
    }
    return cnt;

}

int main()
{
    long long int test,cas,q,i,j,high,low,mid;
    cin>>test;
    for(cas=1; cas<=test; cas++)
    {
        long long int a,res=0,flag=0;
        cin>>q;
        cout<<"Case "<<cas<<": ";
        if(q==1)
        {
            cout<<5<<endl;
            continue;
        }
        high=5*q,low=0,res=0;
        while(low<=high)
        {
            mid=(high+low)/2;
            //  cout<<"Mid "<<mid<<endl;
            a=check(mid);
         //   cout<<"zero cnt "<<a<<endl;
          //  cout<<"q "<<q<<endl;
            if(a==q)
            {
                flag=1;
                res=mid;
            }
          if(a>=q)
                high=mid-1;
            else
                low=mid+1;
        }
        if(flag==1)
            cout<<res<<endl;
        else
            cout<<"impossible"<<endl;
    }
    return 0;
}