using System;
using System.Text;
using System.Linq;

namespace MyCompiler 
{
    class Program 
    {
        public static void Main(string[] args)
        {
            method("68 65 6c 6c 6f 20 77 6f 72 6c 64","Hello World");
            method("48 65 6C 6C 6F 20 77 6F 72 6C 64","Hell0 Madam");
        }
        public static void method(string hexString, string str)
        {
            string strToHex = string.Join("",str.Select(c => Convert.ToByte(c).ToString("X2")));
            string hexToStr = Encoding.UTF8.GetString
                                (
                                     hexString
                                    .Split(' ')
                                    .Select(c => Convert.ToByte(c,16)).ToArray()
                                );
            Console.WriteLine("{0} {1}",strToHex,hexToStr);                           
        }
    }
}