prime_dice = [2,3,5,7,11,13]
merge_dice = [4,6,8,9,10,12]
satisfied = 0
K = int(input())
for pd in prime_dice:
    if not K % pd:
        continue
    num = K // pd
    if num in merge_dice:
        satisfied+=1
ans = satisfied / 6**2
print(ans)