#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-12;
const int N=100000+10,maxn=500+100,inf=0x3f3f3f;

int main()
{
   // cout<<log(2)<<endl;
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout<<setiosflags(ios::fixed)<<setprecision(18);
    ll t,cnt=0;
    cin>>t;
    while(t--){
        ll n;
        cin>>n;
        if(n>1e6)cout<<"Case "<<++cnt<<": "<<log(n)+C+1.0/(2*n)<<endl;
        else
        {
            double ans=0;
            for(ll i=1;i<=n;i++)
                ans+=(1.0/(double)i);
            cout<<"Case "<<++cnt<<": "<<ans<<endl;
        }
    }
    return 0;
}
/*********************
12
1
2
3
4
5
6
7
8
9
90000000
99999999
100000000
*********************/