P, C = map(int, input().split())

D = [2,3,5,7,11,13]
E = [4,6,8,9,10,12]

def keisan(p, c, r):
    if r == C*10+P:
        ans = 0
        for k in p:
            for j in c:
                ans += k*j
        return ans
    elif r%10 != P:
        pp = []
        for e in D:
            for f in p:
                pp.append(e*f)
        return keisan(pp,c,r+1)
    else:
        cc = []
        for e in E:
            for f in c:
                cc.append(e*f)
        return keisan(p,cc,r+10)

print(keisan([1],[1],0)/(6**(P+C)))