from math import gcd

A,B = map(int,input().split())

if A == 0 and B == 0:
    print(0.25)
elif A == 0 or B == 0:
    A = A + B
    A = abs(A)
    ans = 0
    for i in range(100//A):
        ans += 1/pow(i*A+2,i*A+2)
    print(ans)
else:
    A = abs(A)
    B = abs(B)
    g = gcd(A,B)
    ans = 0
    A //= g
    B //= g
    if (A & 1) == (B & 1) :
        for i in range(0,100//g,2):
            ans += 1.0/pow(i*g+2,i*g+2)*(i+1)
    else :
        for i in range(100//g):
            ans += 1.0/pow(i*g+2,i*g+2)*(i+1)
    print(ans)