#include<cstdio>
    #include<cstdlib>
    #include<cstring>
    #include<cmath>
    #include<iostream>
    #include<iomanip>
    #include<algorithm>
    #include<vector>
    #include<map>
    #include<queue>
    #include<bitset>
    #include<set> 
    #define ll long long
    #define lowbit(x) x&(-x)
    #define mp make_pair
    #define rep(i,x,n) for(int i=x;i<=n;i++)
    #define per(i,n,x) for(int i=n;i>=x;i--)
    #define forE(i,x) for(int i=head[x];i;i=nxt[i])
    #define pii pair<int,int>
    #define fi first
    #define se second
    using namespace std;
    const int maxn=2e5+5;
    inline int read()
    {
        int x=0,f=1;char c=getchar();
        while(c<'0'||c>'9')
        {
            if(c=='-') f=-1;
            c=getchar();
        }
        while(c>='0'&&c<='9')
        {
            x=x*10+(c-'0');
            c=getchar();
        }
        return x*f;
    }
    using point_t=long double;  //全局数据类型，可修改为 long long 等

    constexpr point_t eps=1e-8;
    constexpr long double PI=3.1415926535897932384l;

    // 点与向量
    template<typename T> struct point
    {
        T x,y;

        bool operator==(const point &a) const {return (abs(x-a.x)<=eps && abs(y-a.y)<=eps);}
        bool operator<(const point &a) const {if (abs(x-a.x)<=eps) return y<a.y-eps; return x<a.x-eps;}
        bool operator>(const point &a) const {return !(*this<a || *this==a);}
        point operator+(const point &a) const {return {x+a.x,y+a.y};}
        point operator-(const point &a) const {return {x-a.x,y-a.y};}
        point operator-() const {return {-x,-y};}
        point operator*(const T k) const {return {k*x,k*y};}
        point operator/(const T k) const {return {x/k,y/k};}
        T operator*(const point &a) const {return x*a.x+y*a.y;}  // 点积
        T operator^(const point &a) const {return x*a.y-y*a.x;}  // 叉积，注意优先级
        int toleft(const point &a) const {const auto t=(*this)^a; return (t>eps)-(t<-eps);}  // 向量与向量的to-left 测试 1left -1right 0on
        T len2() const {return (*this)*(*this);}  // 向量长度的平方
        T dis2(const point &a) const {return (a-(*this)).len2();}  // 两点距离的平方

        // 涉及浮点数
        long double len() const {return sqrtl(len2());}  // 向量长度
        long double dis(const point &a) const {return sqrtl(dis2(a));}  // 两点距离
        long double ang(const point &a) const {return acosl(max(-1.0l,min(1.0l,((*this)*a)/(len()*a.len()))));}  // 向量夹角
        point rot(const long double rad) const {return {x*cos(rad)-y*sin(rad),x*sin(rad)+y*cos(rad)};}  // 逆时针旋转（给定角度）
        point rot(const long double cosr,const long double sinr) const {return {x*cosr-y*sinr,x*sinr+y*cosr};}  // 逆时针旋转（给定角度的正弦与余弦）
    };

    using Point=point<point_t>;

    // 圆
    struct Circle
    {
        Point c;
        long double r;

        bool operator==(const Circle &a) const {return c==a.c && abs(r-a.r)<=eps;}
        long double circ() const {return 2*PI*r;}  // 周长
        long double area() const {return PI*r*r;}  // 面积


        // 圆与圆关系
        // -1 相同 | 0 相离 | 1 外切 | 2 相交 | 3 内切 | 4 内含
        int relation(const Circle &a) const
        {
            if (*this==a) return -1;
            const long double d=c.dis(a.c);
            if (d>r+a.r+eps) return 0;
            if (abs(d-r-a.r)<=eps) return 1;
            if (abs(d-abs(r-a.r))<=eps) return 3;
            if (d<abs(r-a.r)-eps) return 4;
            return 2;
        }

        // 圆与圆交点
        vector<Point> inter(const Circle &a) const
        {
            const long double d=c.dis(a.c);
            const int t=relation(a);
            if (t==-1 || t==0 || t==4) return vector<Point>();
            Point e=a.c-c; e=e/e.len()*r;
            if (t==1 || t==3) 
            {
                if (r*r+d*d-a.r*a.r>=-eps) return vector<Point>{c+e};
                return vector<Point>{c-e};
            }
            const long double costh=(r*r+d*d-a.r*a.r)/(2*r*d),sinth=sqrt(1-costh*costh);
            return vector<Point>{c+e.rot(costh,-sinth),c+e.rot(costh,sinth)};
        }
    };

    bool cmp(pair<Point,int> u,pair<Point,int> v)
    {
        Point a=u.first,b=v.first;
        const auto quad=[](const Point a)
        {
            if (a.y<-eps) return 1;
            if (a.y>eps) return 4;
            if (a.x<-eps) return 5;
            if (a.x>eps) return 3;
            return 2;
        };
        const int qa=quad(a),qb=quad(b);
        if (qa!=qb) return qa<qb;
        const auto t=a^b;
        // if (abs(t)<=eps) return a*a<b*b-eps;  // 不同长度的向量需要分开
        return t>eps;
    }

    Circle O,c[maxn];
    Point o={0,0};
    vector<pair<Point,int>> e;
    signed main()
    {
        int T=read();
        rep(P,1,T)
        {
            printf("Case #%lld: ",P);
            int n=read(),R=read();
            e.clear();
            O={{0,0},(long double)R};
            rep(i,1,n) c[i]={{(point_t)read(),(point_t)read()},(point_t)read()};
            rep(i,1,n)
            {
                auto v = O.inter(c[i]);
                if((int)v.size() != 2) continue;
                Point x = v[0]-c[i].c, y = v[1]-c[i].c;
                if(v[0].toleft(c[i].c)==-1) swap(v[0],v[1]);
                e.push_back({v[0],0});e.push_back({v[1],1});
            }
            sort(e.begin(),e.end(),cmp);
            long double ans=0.0;
            for(auto i:e)
            {
                for(auto j:e)
                {
                    Point x = i.first, y = j.first;
                    ans=max(ans,x.dis(y));
                }
                Point x = i.first;
                Point rev = -x;
                auto it = lower_bound(e.begin(),e.end(),make_pair(rev,0),cmp);
                auto pre = it;
                if(pre == e.begin()) pre=e.end(),pre--;
                else pre--;
                if(it == e.end()) it = e.begin();
                if(it->second == 0 && pre->second == 1) ans=max(ans,O.r+O.r);
            }
            printf("%.15Lf\n",ans);
        }
    }