import itertools as it
def calc(a):
    res = 1
    for i in a:
        res *= i
    return res
    
P, C = map(int, raw_input().split())
p = [2,3,5,7,11,13]
n = [4,6,8,9,10,12]

ans = 0.0
for pp in it.product(p, repeat = P):
    for nn in it.product(n, repeat = C):
        ans += 1.0 * calc(pp) * calc(nn) / (6.0 ** P * 6.0 ** C)
print "%.10f"%ans