from decimal import Decimal
import decimal
import sys
import math
a,b=map(int,input().split())
decimal.getcontext().prec = 10000
if a==0 and b==0:
    print("0.25")
    sys.exit()
ans=Decimal(0)
for i in range(1,100):
    for j in range(1,100):
        k=math.gcd(a,b)
        if(a!=b and i%k==1 and j%k==1):
            if (i/k+j/k)%2==0 or (a/k+b/k)%2==1:
                ans+=Decimal(1)/Decimal((i+j)**(i+j))
        if a!=b and k==1:
            if (i/k+j/k)%2==0 or (a/k+b/k)%2==1:
                ans+=Decimal(1)/Decimal((i+j)**(i+j))
print(ans)