from math import gcd
A,B=map(int,input().split())

if A==B==0:
    print(0.25)
elif A==0 or B==0:
    C=max(abs(A),abs(B))
    X=0
    for k in range(20):
        h=(k*C+1)
        X+=1/(h**h)
    print(X)
else:
    g=gcd(A,B)
    X=0
    for k in range(20):
        h=(k*g+2)
        X+=(k+1)/(h**h)
    print(X)