import java.util.*;
public class Main{
  public static void main(String[] args) {
    Scanner sc=new Scanner(System.in);
    double n;
    n=sc.nextInt();
    double k;
    if(n%2==0){
      k=n/2;
    }else{
      k=n/2+0.5;
    }
    double d;
    d=k/n;
    System.out.printf("%.10f",k/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