using System;

using static System.Console;

​

public class Program {

    public static void Main() {

        Write($"|{("Hello World".PadBoth(42))}|");

    }

}

​

namespace System {

    public static class StringExt {

        public static string PadBoth(this string str, int length, char character = ' ') => str.PadLeft((length - str.Length) / 2 + str.Length, character).PadRight(length, character);

    }

}