import java.util.*;
class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    
    double a = sc.nextInt();
    double odd1 = 0;
    double odd2 = 0;
    
    for(int i=1 ; i<=a ; i++){
      if(i%2==0){
        odd2++;
      }else{
        odd1++;
      }
    }
    
    System.out.println(odd1/a);
  }
}
  	
    
/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