import sys
from math import gcd
sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


A,B = MI()
g = gcd(A,B)

if g == 0:
    print(1/4)
    exit()

A //= g
B //= g

ans = 0
for i in range(20):
    if i % g != 0:
        continue
    x = i//g
    for j in range(20):
        if j % g != 0:
            continue
        y = j//g
        if (x-y) % 2 == 0:
            ans += 1/((2+i+j)**(2+i+j))
        else:
            if A % 2 == 0 or B % 2 == 0:
                ans += 1/((2+i+j)**(2+i+j))

print(ans)