import java.util.Scanner;
class Main{
  public static void main(String args[]){
    Scanner n=new Scanner(System.in);
    double num=n.nextInt();
    double a;
    if(num%2==1){
      a=(num+1)/2;
    }else{
      a=num/2;
    }
    System.out.println(a/num);
  }
}
/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