from itertools import product, combinations, permutations, groupby, accumulate
P, C = map(int, input().split())
sosu = [2, 3, 5, 7, 11, 13]
gose = [4, 6, 8, 9, 10, 12]

total = 0
for pat1 in product([i for i in range(6)], repeat=P):
    # P個の 0-5 の数字
    a = 1
    for num in pat1:
        a *= sosu[num]
    for pat2 in product([i for i in range(6)], repeat=C):
        b = a
        for num in pat2:
            b *= gose[num]
        total += b

ans = total/6**(P + C)
print(ans)