#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;

inline ll rd() {
    ll x = 0;
    bool f = 0;
    char c = getchar();
    for (; !isdigit(c); c = getchar()) f |= (c == '-');
    for (; isdigit(c); c = getchar()) x = x * 10 + (c ^ 48);
    return f ? -x : x;
}

#define eb emplace_back
#define all(s) (s).begin(), (s).end()
#define rep(i, a, b) for (int i = (a); i <= (b); ++i)
#define per(i, a, b) for (int i = (a); i >= (b); --i)

const ld PI = 3.1415926535897932384626433832795;
const ld a90 = atan(1) * 2;
const ld a180 = a90 * 2, a270 = a90 * 3, a360 = a90 * 4;
const ld dlt[2][2] = {0, a180, a360, a180};

inline ld angle(ld x, ld y) { // counterclockwise, start from (1, 0)
    if (fabs(x) < 1e-15) return a90 * (1 + 2 * (y < 0));
    else return atan(y / x) + dlt[y < 0][x < 0];
}

int testcase = 0;

inline void work() {
    int n = rd();
    ld R = rd();
    ld R2 = R * R;
    vector<pair<ld, ld>> s;
    rep(i, 1, n) {
        ld x = rd(), y = rd(), rr = rd();
        if (x * x + y * y >= (rr + R) * (rr + R)) continue;
        ld theta0 = angle(x, y);
        ld rho02 = x * x + y * y;
        ld rho0 = sqrt(rho02);
        ld dlt = acos((rho02 + R2 - rr * rr) / (2 * rho0 * R));
        ld l = theta0 - dlt;
        ld r = theta0 + dlt;
        if (r > 2 * PI) {
            r -= 2 * PI;
            l -= 2 * PI;
        }
        if (l < 0) {
            s.eb(l + 2 * PI, 2 * PI);
            s.eb(0, r);
        } else s.eb(l, r);
    }
    vector<pair<ld, ld>> segs;
    ld nw = 0;
    sort(all(s));
    for (auto [l, r] : s) {
        if (nw != l) segs.eb(nw, l);
        nw = r;
    }
    if (nw != 2 * PI) segs.eb(nw, 2 * PI);
    auto calc = [&](ld ang) {
        return sqrt(R2 * (2 - 2 * cos(ang)));
    };
    ld ans = 0;
    for (auto [l1, r1] : segs)
        for (auto [l2, r2] : segs) {
            ld nwl = l1 - r2, nwr = r1 - l2;
            ans = max(ans, calc(nwl));
            ans = max(ans, calc(nwr));
            if (nwl < -PI && -PI < nwr) ans = max(ans, 2 * R);
            if (nwl < PI && PI < nwr) ans = max(ans, 2 * R);
        }
    printf("Case #%d: %.18lf\n", ++testcase, (double)ans);
}

int main() {
    per(t, rd(), 1) work();
    return 0;
}