k = int(input())
primes = [2, 3, 5, 7, 11, 13]
composites = {4, 6, 8, 9, 10, 12}

if k == 0:
    print("0.00000000000000000")
else:
    count = 0
    for p in primes:
        if k % p == 0:
            c = k // p
            if c in composites:
                count += 1
    probability = count / 36
    print("{0:.17f}".format(probability))