import sys
from math import gcd
def MI(): return map(int,sys.stdin.readline().rstrip().split())


A,B = MI()

if A == B == 0:
    print(1/4)
    exit()

g = gcd(A,B)
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
        # (1+i,1+j)に辿り着けるか
        if (x-y) % 2 == 0 or (A*B) % 2 == 0:
            ans += 1/((2+i+j)**(2+i+j))

print(ans)