#!/usr/bin/env python3
#fileencoding: utf-8

prime = [2,3,5,7,11,13]
synth = [4,6,8,9,10,12]
K = int(input())

count = 0
for i in prime:
    for j in synth:
        if i*j == K:
            count += 1
print(count/36.0)