import java.util.*;
public class Main{
  public static void main(String[]args){
    Scanner sc=new Scanner(System.in);
    int n=sc.nextInt();
    double m=n/2;
    double k=Math.floor(m);
    double l=(n-k)/n;
    System.out.println(l);
  }
}



/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