prime_dice = [2,3,5,7,11,13]
comp_dice = [4,6,8,9,10,12]
all_possibilities = [1]
P,C = map(int,raw_input().split())

def multiply_list(list1,list2):
    result = []
    for i in list1:
        result.extend(map(lambda x : i * x ,list2))
    return result

for i in range(P):
    all_possibilities = multiply_list(all_possibilities,prime_dice)

for i in range(C):
    all_possibilities = multiply_list(all_possibilities,comp_dice)

print sum(all_possibilities)/(6.0**(P+C))