from math import gcd
from collections import deque
A, B = map(int, input().split())
G = gcd(A, B)
Closed = {(1, 1)}
ans = 0.25
Dx = [G,0,-G,0,A,A,-A,-A,B,B,-B,-B]
Dy = [0,G,0,-G,B,-B,B,-B,A,-A,A,-A]
q = deque([(1, 1)])
for i in range(10**5):
    if not q:
        break
    x, y = q.popleft()
    for dx, dy in zip(Dx, Dy):
        ux, uy = x+dx, y+dy
        if (ux, uy) not in Closed:
            Closed.add((ux, uy))
            q.append((ux, uy))
            if 1 <= ux < 20 and 1 <= uy < 20:
                if not (A+B&1 == 0 and ux+uy&1):
                    ans += 1 / ((ux+uy)**(ux+uy))
print(ans)