from math import gcd
A, B = map(int, input().split())
A = abs(A)
B = abs(B)
ans = 0
if A==B:
  for i in range(1,21):
    for j in range(1,21):
      if (i+j)%(2*A)==0:
        ans += 1/pow(i+j,i+j)
else:
  g = gcd(A,B)
  for i in range(1,21,g):
    for j in range(1,21,g):
      ans += 1/pow(i+j,i+j)
print(ans)