An open-top box having a square bottom is placed on the floor. You see a number of needles vertically planted on its bottom.

You want to place a largest possible spheric balloon touching the box bottom, interfering with none of the side walls nor the needles.

Java Specific: Submitted Java programs may not use "java.awt.geom.Area". You may use it for your debugging purposes.

Figure H.1 shows an example of a box with needles and the corresponding largest spheric balloon. It corresponds to the first dataset of the sample input below.

<image>
Figure H.1. The upper shows an example layout and the lower shows the largest spheric balloon that can be placed.



Input

The input is a sequence of datasets. Each dataset is formatted as follows.


n w
x1 y1 h1
:
xn yn hn


The first line of a dataset contains two positive integers, n and w, separated by a space. n represents the number of needles, and w represents the height of the side walls.

The bottom of the box is a 100 × 100 square. The corners of the bottom face are placed at positions (0, 0, 0), (0, 100, 0), (100, 100, 0), and (100, 0, 0).

Each of the n lines following the first line contains three integers, xi, yi, and hi. (xi, yi, 0) and hi represent the base position and the height of the i-th needle. No two needles stand at the same position.

You can assume that 1 ≤ n ≤ 10, 10 ≤ w ≤ 200, 0 < xi < 100, 0 < yi < 100 and 1 ≤ hi ≤ 200. You can ignore the thicknesses of the needles and the walls.

The end of the input is indicated by a line of two zeros. The number of datasets does not exceed 1000.

Output

For each dataset, output a single line containing the maximum radius of a balloon that can touch the bottom of the box without interfering with the side walls or the needles. The output should not contain an error greater than 0.0001.

Example

Input

5 16
70 66 40
38 52 20
40 35 10
70 30 10
20 60 10
1 100
54 75 200
1 10
90 10 1
1 11
54 75 200
3 10
53 60 1
61 38 1
45 48 1
4 10
20 20 10
20 80 10
80 20 10
80 80 10
0 0


Output

26.00000
39.00000
130.00000
49.49777
85.00000
95.00000

Source: aizu | Difficulty: UNKNOWN_DIFFICULTY


Solutions:
from math import sqrt

def getcircle(nee, R):
	(x, y, h) = nee
	if R <= h:
		return (x, y, R)
	r = sqrt(R ** 2 - (R - h) ** 2)
	return (x, y, r)

def crosscircle(c1, c2):
	(x1, y1, r1) = c1
	(x2, y2, r2) = c2
	if (x1 - x2) ** 2 + (y1 - y2) ** 2 > (r1 + r2) ** 2:
		return ()
	elif x1 == x2 and y1 == y2:
		return ()
	elif (x1 - x2) ** 2 + (y1 - y2) ** 2 == (r1 + r2) ** 2:
		x = (x1 * r2 + x2 * r1) / (r1 + r2)
		y = (y1 * r2 + y2 * r1) / (r1 + r2)
		return ((x, y),)
	elif y1 == y2:
		x = (r1 ** 2 - r2 ** 2 - x1 ** 2 + x2 ** 2) / (2 * (x2 - x1))
		if y1 ** 2 - (y1 ** 2 - r1 ** 2 + (x - x1) ** 2) >= 0:
			yans1 = y1 + sqrt(y1 ** 2 - (y1 ** 2 - r1 ** 2 + (x - x1) ** 2))
			yans2 = y1 - sqrt(y1 ** 2 - (y1 ** 2 - r1 ** 2 + (x - x1) ** 2))
			return ((x, yans1), (x, yans2))
		else:
			return ()
	elif x1 == x2:
		y = (r1 ** 2 - r2 ** 2 - y1 ** 2 + y2 ** 2) / (2 * (y2 - y1))
		if x1 ** 2 - (x1 ** 2 - r1 ** 2 + (y - y1) ** 2) >= 0:
			xans1 = x1 + sqrt(x1 ** 2 - (x1 ** 2 - r1 ** 2 + (y - y1) ** 2))
			xans2 = x1 - sqrt(x1 ** 2 - (x1 ** 2 - r1 ** 2 + (y - y1) ** 2))
			return ((xans1, y), (xans2, y))
		else:
			return ()
	else:
		A = ((x1 - x2) / (y1 - y2)) ** 2 + 1
		B = (x1 - x2) * (r1 ** 2 - r2 ** 2 - x1 ** 2 + x2 ** 2 + (y1 - y2) ** 2) / (y1 - y2) ** 2 - 2 * x1
		C = ((r1 ** 2 - r2 ** 2 - x1 ** 2 + x2 ** 2 + (y1 - y2) ** 2) / (2 * (y1 - y2))) ** 2 + x1 ** 2 - r1 ** 2
		if B ** 2 - 4 * A * C >= 0:
			xans1 = (-B + sqrt(B ** 2 - 4 * A * C)) / (2 * A)
			xans2 = (-B - sqrt(B ** 2 - 4 * A * C)) / (2 * A)
			yans1 = -(r1 ** 2 - r2 ** 2 - x1 ** 2 + x2 ** 2 - y1 ** 2 + y2 ** 2) / (2 * (y1 - y2)) - xans1 * (x1 - x2) / (y1 - y2)
			yans2 = -(r1 ** 2 - r2 ** 2 - x1 ** 2 + x2 ** 2 - y1 ** 2 + y2 ** 2) / (2 * (y1 - y2)) - xans2 * (x1 - x2) / (y1 - y2)
			return ((xans1, yans1), (xans2, yans2))
		else:
			return ()
while True:
	(n, w) = map(int, input().split())
	if n == w == 0:
		break
	nees = [tuple(map(float, input().split())) for i in range(n)]
	eps = 1e-06
	U = 130
	L = 0
	while U - L > 0.0001:
		ok = False
		R = (U + L) / 2
		cirs = []
		points = []
		if R > w:
			l = sqrt(R ** 2 - (R - w) ** 2)
		else:
			l = R
		if l >= 100 - l:
			U = R
			continue
		for nee in nees:
			c = getcircle(nee, R)
			cirs.append(c)
		for c in cirs:
			(x, y, r) = c
			if abs(l - x) <= r:
				if l <= y + sqrt(r ** 2 - (x - l) ** 2) <= 100 - l:
					points.append((l, y + sqrt(r ** 2 - (x - l) ** 2)))
				if l <= y - sqrt(r ** 2 - (x - l) ** 2) <= 100 - l:
					points.append((l, y - sqrt(r ** 2 - (x - l) ** 2)))
			if abs(l - y) <= r:
				if l <= x + sqrt(r ** 2 - (y - l) ** 2) <= 100 - l:
					points.append((x + sqrt(r ** 2 - (y - l) ** 2), y))
				if l <= x - sqrt(r ** 2 - (y - l) ** 2) <= 100 - l:
					points.append((x - sqrt(r ** 2 - (y - l) ** 2), y))
			if abs(100 - l - x) <= r:
				if l <= y + sqrt(r ** 2 - (x + l - 100) ** 2) <= 100 - l:
					points.append((100 - l, y + sqrt(r ** 2 - (x + l - 100) ** 2)))
				if l <= y - sqrt(r ** 2 - (x + l - 100) ** 2) <= 100 - l:
					points.append((100 - l, y - sqrt(r ** 2 - (x + l - 100) ** 2)))
			if abs(100 - l - y) <= r:
				if l <= x + sqrt(r ** 2 - (100 - l - y) ** 2) <= 100 - l:
					points.append((x + sqrt(r ** 2 - (100 - l - y) ** 2), y))
				if l <= x - sqrt(r ** 2 - (100 - l - y) ** 2) <= 100 - l:
					points.append((x - sqrt(r ** 2 - (100 - l - y) ** 2), y))
		for i in range(n):
			if n != 1 and i != n - 1:
				for j in range(i + 1, n):
					p = crosscircle(cirs[i], cirs[j])
					if p == ():
						continue
					for a in p:
						if l <= a[0] <= 100 - l and l <= a[1] <= 100 - l:
							points.append(a)
		points.append((l, l))
		points.append((100 - l, l))
		points.append((l, 100 - l))
		points.append((100 - l, 100 - l))
		for p in points:
			if not l <= p[0] <= 100 - l:
				continue
			if not l <= p[1] <= 100 - l:
				continue
			pok = True
			for c in cirs:
				if (p[0] - c[0]) ** 2 + (p[1] - c[1]) ** 2 <= (c[2] - eps) ** 2:
					pok = False
					break
			if pok:
				ok = True
				break
		if ok:
			L = R
		else:
			U = R
	print(R)


from math import sqrt

def get_cross_point_of_circles(x1, y1, r1, x2, y2, r2):
	rr0 = (x2 - x1) ** 2 + (y2 - y1) ** 2
	xd = x2 - x1
	yd = y2 - y1
	rr1 = r1 ** 2
	rr2 = r2 ** 2
	cv = rr0 + rr1 - rr2
	sv2 = 4 * rr0 * rr1 - cv ** 2
	if sv2 < 0:
		return None
	sv = sqrt(sv2)
	return ((x1 + (cv * xd - sv * yd) / (2.0 * rr0), y1 + (cv * yd + sv * xd) / (2.0 * rr0)), (x1 + (cv * xd + sv * yd) / (2.0 * rr0), y1 + (cv * yd - sv * xd) / (2.0 * rr0)))

def get_solution_of_quadratic(a, b, c):
	if b ** 2 >= 4 * a * c:
		return {(-b + sqrt(b ** 2 - 4 * a * c)) / (2 * a), (-b - sqrt(b ** 2 - 4 * a * c)) / (2 * a)}
	else:
		return {}

def get_nearest_wall(x, y):
	if y <= x:
		if y <= 100 - x:
			return (x, 0)
		else:
			return (100, y)
	elif y <= 100 - x:
		return (0, y)
	else:
		return (x, 100)
while True:
	(n, w) = map(int, input().split())
	if n == w == 0:
		break
	xyh = [tuple(map(float, input().split())) for _ in range(n)]
	m = (2500 + w ** 2) / (2 * w) if w < 50 else 50
	P = (50, 50, m)
	flag0 = True
	for k in range(n):
		if (50 - xyh[k][0]) ** 2 + (50 - xyh[k][1]) ** 2 + max(0.0, m - xyh[k][2]) ** 2 <= m ** 2:
			flag0 = False
	if flag0:
		print(m)
		continue
	l = 0
	r = 130
	while abs(r - l) >= 0.0001:
		m = (l + r) / 2
		flag = False
		for i in range(n):
			if n != 1 and i != n - 1:
				for j in range(i + 1, n):
					h1 = min(xyh[i][2], m)
					h2 = min(xyh[j][2], m)
					P = get_cross_point_of_circles(xyh[i][0], xyh[i][1], sqrt(2 * h1 * m - h1 ** 2), xyh[j][0], xyh[j][1], sqrt(2 * h2 * m - h2 ** 2))
					if P is None:
						continue
					for p in P:
						if 0 <= p[0] <= 100 and 0 <= p[1] <= 100:
							(wx, wy) = get_nearest_wall(p[0], p[1])
							if (wx - p[0]) ** 2 + (wy - p[1]) ** 2 + max(0, m - w) ** 2 >= m ** 2:
								flag2 = True
								for k in range(n):
									if k != i and k != j:
										if (p[0] - xyh[k][0]) ** 2 + (p[1] - xyh[k][1]) ** 2 + max(0.0, m - xyh[k][2]) ** 2 <= m ** 2:
											flag2 = False
								if flag2:
									flag = True
			(x, y, h) = xyh[i]
			h = min(h, m)
			S1 = get_solution_of_quadratic(2, -2 * (x + y), x ** 2 + y ** 2 - 2 * m * h + h ** 2)
			S2 = get_solution_of_quadratic(2, -2 * (x + 100 - y), x ** 2 + (100 - y) ** 2 - 2 * m * h + h ** 2)
			for s in S1:
				if 0 <= s <= 100:
					(wx, wy) = get_nearest_wall(s, s)
					if (wx - s) ** 2 + (wy - s) ** 2 + max(0, m - w) ** 2 >= m ** 2:
						flag2 = True
						for k in range(n):
							if k != i:
								if (s - xyh[k][0]) ** 2 + (s - xyh[k][1]) ** 2 + max(0.0, m - xyh[k][2]) ** 2 <= m ** 2:
									flag2 = False
						if flag2:
							flag = True
			for s in S2:
				if 0 <= s <= 100:
					(wx, wy) = get_nearest_wall(s, 100 - s)
					if (wx - s) ** 2 + (wy - (100 - s)) ** 2 + max(0, m - w) ** 2 >= m ** 2:
						flag2 = True
						for k in range(n):
							if k != i:
								if (s - xyh[k][0]) ** 2 + (100 - s - xyh[k][1]) ** 2 + max(0.0, m - xyh[k][2]) ** 2 <= m ** 2:
									flag2 = False
						if flag2:
							flag = True
		if flag:
			l = m
		else:
			r = m
	print(m)