# -*- coding:utf-8 -*-
pd = [2, 3, 5, 7, 11, 13]
cd = [4, 6, 8, 9, 10, 12]
if __name__ == '__main__':
    k = int(input())
    cnt = 0
    for p in pd:
        for c in cd:
            if p * c == k:
                cnt += 1
    print(cnt / (len(pd) * len(cd)))