import java.util.Scanner;
public class Main{
  public static void main(String[] args){
  Scanner sc = new Scanner(System.in);
  int N = sc.nextInt();
  double c=0;
  for(int i=1;i<=N;i++){
    if(i%2==1){
      c++;
    }
  }
  System.out.println(c/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