from math import log2
p,q = map(int,input().split())
def f(n) :
    return p+q*n*log2(n)-n*n
top = 4*(10**8)
bot = 1
while top - bot > 10**(-7):
    mid = (top + bot)/2
    if f(mid) >= 0:bot = mid
    else:top = mid
print(bot)