# coding: utf-8

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

K = int(input())
count = 0

for p in prime_dice:
    if K % p != 0:
        continue
    else:
        for c in compn_dice:
            if (K / p) / c == 1:
                count += 1
                break

prob = count / 36
print("{:.13f}".format(prob))