using System;
using System.Collections;
using System.Collections.Generic;
 
class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		int[] pd=new int[]{2,3,5,7,11,13};
		int[] cd=new int[]{4,6,8,9,10,12};
		
		double cnt=0.0;
		for(int i=0;i<6;i++){
			for(int j=0;j<6;j++){
				if(pd[i]*cd[j]==K)cnt+=1.0;
			}
		}
		Console.WriteLine(cnt/36);
		
		
		
	}
	int K;
	public Sol(){
		K=ri();
	}




	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(){return Console.ReadLine().Split(' ');}
	static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));}
	static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));}
	static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));}
}