from math import gcd
A, B = map(int, input().split())
ans = 0
if A==B:
  for i in range(1,21,abs(A)):
    ans += 1/pow(i+i,i+i)
else:
  g = gcd(A,B)
  for i in range(1,21):
    for j in range(1,21):
      if g==1 or (i%g==1 and j%g==1):
        ans += 1/pow(i+j,i+j)
print(ans)