import java.util.Scanner;
 
public class Main{
   public static void main(String args[]){
     Scanner sc = new Scanner(System.in);
     int N = sc.nextInt();
     int S = N / 2;
     double K = (double)(N - S) / (double)N;
     System.out.println(K);
   }
}
/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