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
if a // g % 2 == 1 and b // g % 2 == 1:
    for i in range(1000):
        xy = 2 + 2 * (i + 1) * g
        if xy > 1000:
            break
        ans += (i + 1) / xy ** xy
    print('{0:.10f}'.format(ans))
    exit(0)
for i in range(1000):
    xy = 2 + i * g
    if xy > 1000:
        break
    ans += (i + 1) / xy ** xy
print('{0:.10f}'.format(ans))