lightoj1138

二分

#include<map>
#include<set>
#include<cmath>
#include<queue>
#include<stack>
#include<vector>
#include<cstdio>
#include<cassert>
#include<iomanip>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
#define C 0.5772156649
#define pi acos(-1.0)
#define ll long long
#define mod 1000000007
#define ls l,m,rt<<1
#define rs m+1,r,rt<<1|1
#pragma comment(linker, "/STACK:1024000000,1024000000")

using namespace std;

const double g=10.0,eps=1e-7;
const int N=100000+10,maxn=500+100,inf=0x3f3f3f;

ll getzero(ll k)
{
    ll ans=0;
    while(k){
        ans+=k/5;
        k/=5;
    }
    return ans;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll t,cnt=0;
    cin>>t;
    while(t--){
        ll n;
        cin>>n;
        ll l=1,r=500000000;
        while(l<=r){
            ll m=(l+r)/2;
            if(getzero(m)<n)l=m+1;
            else r=m-1;
        }
        if(getzero(l)==n)cout<<"Case "<<++cnt<<": "<<l<<endl;
        else cout<<"Case "<<++cnt<<": impossible"<<endl;
    }
    return 0;
}
/*********************
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*********************/