import java.util.Scanner;
 public class Main {
 
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        
      int a =N/2;
      int b =(N/2)+1;
      
      double c =a;
      double d =b;
      
      if(N%2==0){
      System.out.print(c/N);
      }
      else if(N%2!=0){
      System.out.print(d/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