P,C = map(int,raw_input().split())
dice1 = [2, 3, 5, 7, 11, 13]
dice2 = [4, 6, 8, 9, 10, 12]

def dice(cnt1, cnt2):
    if (cnt1 == 0 and cnt2 == 0):
        return 1.0
    res = 0
    if (cnt1 > 0 and cnt2 > 0):
        for x in dice1:
            for y in dice2:
                res += (x * y) * (1 / 36.0) * dice(cnt1 - 1, cnt2 - 1)
    elif (cnt1 > 0):
        for x in dice1:
            res += x * (1 / 6.0) * dice(cnt1 - 1, cnt2)
    elif (cnt2 > 0):
        for x in dice2:
            res += x * (1 / 6.0) * dice(cnt1, cnt2 - 1)
    return res
            
print ("%.20lf" % (dice(P, C)))