import math
A,B = map(int,input().split())
MAX = 10
if A >= pow(10,9) or B >= pow(10,9):
  MAX = 3
ans = 0
if abs(A) == abs(B):
  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)
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)