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

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

def multi(list1, list2):
    return [item1 * item2 for item1 in list1 for item2 in list2]

dice = [1]*6
for loop in xrange(P):
    dice = multi(dice, prime)

for loop in xrange(C):
    dice = multi(dice, compo)

exp = 1.0 * sum(dice) / len(dice)
print exp