import math


def f(x):
    return x ** 2 - p - q * x * math.log2(x)


p, q = map(int, input().split())
i = 0
left = 0
right = 10 ** 15
eps = 10 ** (-7)
while True:
    diff = f(half)
    if abs(diff) < eps:
        break
    elif diff > 0:
        right = half
        half = (left + right) / 2
    else:
        left = half
        half = (left + right) / 2
print(half)