import sys

if sys.platform == 'ios':
	sys.stdin = open('in.txt')
sys.setrecursionlimit(10**6)

k=int(input())

ans=0
for i in [2,3,5,7,11,13]:
	for j in [4,6,8,9,10,12]:
		if k==i*j:
			ans=1/(6*6)
			break
print(ans)