from math import gcd
A,B=map(int,input().split())

if A==B==0:
    print(0.25)
elif A==0 or B==0:
    C=max(abs(A),abs(B))
    if C>=9:
        print(0.25)
    else:
        print([0.291285997062663540407282590596, 0.253927743175264566674009102034,0.250320059608149804379393070974, 0.250021433570507634574389368789,
            0.250001214265791058668395963380, 0.250000059604644865383370307350,0.250000002581174791767407290614, 0.250000000100000000000025415281,
            0.250000000003504938994813934513, 0.250000000000112156654784615087,0.250000000000003301690955230119, 0.250000000000000089992745297813,
            0.250000000000000002283658260521, 0.250000000000000000054210108624,0.250000000000000000001208838648, 0.250000000000000000000025415281,
            0.250000000000000000000000505454, 0.250000000000000000000000009537,0.250000000000000000000000000171, 0.250000000000000000000000000003][C-1])
else:
    g=gcd(A,B)
    X=0

    if g<=20:
        T=10
    else:
        T=2

    if (A//g)%2==(B//g)%2==1:
        for k in range(T):
            h=2*k*g+2
            X+=(2*k+1)/(h**h)
    else:
        for k in range(T):
            h=k*g+2
            X+=(k+1)/(h**h)
    print(X)