from functools import reduce
from operator import mul
from itertools import product, permutations, combinations, accumulate, cycle, combinations_with_replacement
from string import ascii_uppercase, ascii_lowercase, ascii_letters, digits, hexdigits, octdigits

prod = lambda l: reduce(mul, l, 1)
prodmod = lambda l, mod: reduce(lambda x, y: mul(x,y)%mod, l)

P, C = map(int, input().split())
saikoro = {}
for i in product([2,3,5,7,11,13], repeat=P):
    for j in product([4,6,8,9,10,12], repeat=C):
        p = prod(i)*prod(j)
        saikoro[p] = saikoro.get(p, 0) + 1

ans = 0
for key, cnt in saikoro.items():
    ans += key * cnt / (6**(P+C))
print(ans)