import java.util.*;
public class Main {
   public static void main(String[] args) {  
      Scanner sc = new Scanner(System.in);
      
      int n = sc.nextInt();
      
      System.out.println(Math.ceil(n / 2.0) / n * 1.0);
   }
}
/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