dice1 = [2, 3, 5, 7, 11, 13]
dice2 = [4, 6, 8, 9, 10, 12]
K = int(raw_input())
cnt = 0
for i in range(0, 6):
	for j in range(0, 6):
		if dice1[i]*dice2[j] == K: cnt += 1
print float(cnt)/36