#include<bits/stdc++.h>
using namespace std;
#define N 505
#define db double
int n,m,C,in[N];
db f[N][N];
struct node{
    int x,v;
    node(){
        x=v=0;
    }
    node(int _x,int _v){
        x=_x,v=_v;
    }
    bool operator<(const node b)const {
        return x<b.x;
    }
}L[N],R[N];
void sol(){
    cin>>C>>n;int nl=0,nr=0;
    for(int i=1,x;i<=n;++i){
        cin>>x;in[i]=x;
        if(x<0)L[++nl].x=-x;
        else R[++nr].x=x;
    }
    for(int i=1,nl=0,nr=0,v;i<=n;++i){
        cin>>v;
        if(in[i]<0)L[++nl].v=v;
        else R[++nr].v=v;
    }
    sort(L+1,L+nl+1);sort(R+1,R+nr+1);
    for(int i=0;i<=nl;++i)for(int j=0;j<=nr;++j)f[i][j]=1e18;
    f[0][0]=0;db ans=1e18;
    for(int i=0;i<=nl;++i)for(int j=0;j<=nr;++j)if(f[i][j]<1e18){
        db w=0;
        for(int k=i+1;k<=nl;++k){
            w=max(w,1.0*(L[k].x+L[k].v*f[i][j])/(C-L[k].v));
            f[k][j]=min(f[k][j],f[i][j]+w+w);
            // cout<<i<<" "<<j<<' '<<k<<" "<<w<<" L\n";
            if(k==nl&&j==nr)ans=min(ans,f[i][j]+w);
        }
        w=0;
        for(int k=j+1;k<=nr;++k){
            w=max(w,1.0*(R[k].x+R[k].v*f[i][j])/(C-R[k].v));
            f[i][k]=min(f[i][k],f[i][j]+w+w);
            // cout<<i<<" "<<j<<" "<<k<<" "<<w<<" R\n";
            if(i==nl&&k==nr)ans=min(ans,f[i][j]+w);
        }
        // cout<<"dp "<<i<<" "<<j<<" "<<f[i][j]<<"\n";
    }
    cout<<fixed<<setprecision(10)<<ans<<"\n";
}
signed main(){
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int T;cin>>T;
    for(int i=1;i<=T;++i)cout<<"Case #"<<i<<": ",sol();
}