# -*- coding: utf-8 -*-

import random

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

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

total = 0
num = 1000000

for i in xrange(num):
    add = 1
    for p in xrange(P):
        add *= random.choice(primes)
    for c in xrange(C):
        add *= random.choice(composite)
    total += add

print "%.9f" % (1.0 * total / num)