import math
A,B = map(int,input().split())
A = abs(A); B = abs(B)
if A == 0 and B == 0:
  ans = 0.25; print(ans); exit()
MAX = 100

ans = 0
if A == B:
  if A >= 10:
    MAX = 1
  for y in range(MAX):
    for x in range(MAX):
      if y%2 == 0:
        kx = 1 + 2*A*x
        ky = 1 + A*y
      else:
        kx = 1 + 2*A*x + A
        ky = 1 + A*y
      temp = 1/pow(kx+ky,kx+ky)
      #print(x,y,kx,ky,temp)
      ans += temp
  print(ans);exit()
  
k = math.gcd(A,B)
#print(k)　片方ゼロならゼロではない数字がk
if k >= 10:
  MAX = 1
ans = 0
for y in range(MAX):
  for x in range(MAX):
    kx = 1 + k*x
    ky = 1 + k*y
    temp = 1/pow(kx+ky,kx+ky)
    #print(kx,ky,temp)
    ans += temp
print(ans)