a, b = map(abs, map(int, input().split()))
if a > b:
    a, b = b, a
if b == 0:
    print(0.25)
    exit(0)
from math import gcd
g = gcd(a, b)
ans = 0
for i in range(1000):
    xy = 2 + i * g
    ans += (i + 1) / xy ** xy
print(ans)