
import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;


    
    public class Main{
        
        

   public static void main (String[] args)  throws IOException{

      Scanner sc=new Scanner(System.in);
      int N=0;
      if(sc.hasNextInt())
      {
          N=sc.nextInt();
      }
      int count=0;
      for(int i=0;i<=N;i++)
      {
          if(i%2!=0)
          {
              count++;
          }
      }
      
     
     double X=(double)count/N;
      System.out.println(X);
        
       
   }
   
}
   
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz