#include<bits/stdc++.h>

#define fi first

#define se second

#define mp make_pair

#define pb push_back

#define pi acos(-1.0)

#define ll long long

#define mod 1000000007

#define C 0.5772156649

#define ls l,m,rt<<1

#define rs m+1,r,rt<<1|1

#define pii pair<int,int>

using namespace std;

const double g=10.0,eps=1e-;

const int N=+,maxn=+,inf=0x3f3f3f3f;

double dp[N];

vector<int>v[N];

int main()

{

    for(int i=;i<=;i++)

    {

        for(int j=;j*j<=i;j++)

        {

            if(i%j==)

            {

                v[i].pb(j);

                if(j*j!=i)v[i].pb(i/j);

            }

        }

    }

    for(int i=;i<=;i++)

    {

        double te=;

        for(int j=;j<v[i].size();j++)

        {

            int x=v[i][j];

            te+=+dp[x];

        }

        dp[i]=te/(v[i].size()-);

    }

    int res=,t;

    scanf("%d",&t);

    while(t--)

    {

        int n;

        scanf("%d",&n);

        printf("Case %d: %.10f\n",++res,dp[n]);

    }

    return ;

}

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