# coding: utf-8
# Your code here!
import sys
readline = sys.stdin.readline
read = sys.stdin.read

#n,m,s = [int(i) for i in readline().split()]
p,q = [int(i) for i in readline().split()]

from math import log
def f(x,p,q):
    return p + q*x*log(x,2) - x*x

ok = 1.0
ng = 10**18

for _ in range(100):
    mid = (ok+ng)/2
    if f(mid,p,q) > 0:
        ok = mid
    else:
        ng = mid

print(ok)