import java.util.*;

public class Main{

public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  double N = sc.nextDouble();
  System.out.println((N - Math.floor(N/2)) / 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