from collections import deque

p,q=map(int,input().split())
p/=100
q/=100
ANS=1/3

Q=deque([(1/3,p)])
# ここに至る確率、pの値



for tests in range(100000):
    c,p=Q.popleft()
    ANS+=(1/2*p+1/3*(1-p))*c

    Q.append((c*p/2,max(0,p-q)))
    Q.append((c*(1-p)/3,min(1,p+q)))

print(ANS)