a = float(raw_input())
b = float(raw_input())

l = 0
p = 10

x1 = a*0 + b
x2 = a*10 + b

tmp = x1 * x2

X = (p - l)/2

if tmp <=0:
	while abs(a*X + b) > 0.001:
		if((a*X+b)*(a*l+b) <= 0):
			p = X
		elif ((a*X+b)*(a*p+b) <= 0):
			l = X
		X = (p - l) / 2
	print X
else:
	print "BRAK"