#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <vector>
#include <queue>
#include <string>
#include <functional>
#include <iostream>


using namespace std;
 
//namaega184 
 
int main(){
	int k;scanf("%d",&k); 
	int a[10]={2,3,5,7,11,13},b[10]={4,6,8,9,10,12};
	int c[200]={};
	for(int i=0;i<6;i++)for(int j=0;j<6;j++)c[a[i]*b[j]]++;
	printf("%.13f\n",(double)c[k]/36 );  
	return 0; 
}