import java.util.Scanner;
 public class Main{
   public static void main(String[]args){
     Scanner s = new Scanner(System.in);
     int n = s.nextInt();
     int a = n/2;
     int b = (n/2)+1;
     double c = a;
     double d = b;
     
     if(n%2==0){
       System.out.println(c/n);
     }else if(n%2!=0){
       System.out.println(d/n);
     }
   }
 }
/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