# -*- coding: utf-8 -*-
N = input()
AD = [2,3,5,7,11,13]
BD = [4,6,8,9,10,12]
Alist = [0]*157
for i in range(0,6):
    for j in range(0,6):
        Alist[AD[i]*BD[j]] += 1
if 1 <= N <= 156:
    print Alist[N] / 36.0
else:
    print 0