p, q = map(int, input().split())

import math

def is_ok(n):
    if p+q*n*math.log2(n)-n**2 >= 0:
        return True
    else:
        return False

l = 0
r = 10**18
for i in range(10**4):
    c = (l+r)/2
    if is_ok(c):
        l = c
    else:
        r = c
print(l)