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

k = int(input())

if k == 0:
    print("0.00000000000000000")
else:
    count = 0
    for p in prime:
        if k % p != 0:
            continue
        s = k // p
        if s in composite:
            count += 1
    probability = count / 36
    print("{0:.16f}".format(probability))