#include<bits/stdc++.h>
using namespace std;
int main()
{
int t,z,ans,i;
int mid,l,r,x;
scanf("%d",&t);
{
for(i=1;i<=t;i++)
{
cin>>z;
l=1; r=5e8; mid=(l+r)/2;
while(l!=mid)
{
ans=0;
x=mid;
while(x)
{
ans+=x/5;
x/=5;
}
if(ans>=z)
r=mid;
else
l=mid;
mid=(l+r)/2;
}
ans=0;
x=mid+1;
while(x)
{
ans+=x/5;
x/=5;
}
printf("Case %d: ",i);
if(ans==z)
printf("%d\n",mid+1);
else printf("impossible\n");
}
}
return 0;
}
f(n)=n/5+f(n/5) 阶乘后0的个数 n>5