How to add a property to another class from different class file in C#,asp.net ?

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Human h = new Human();
            Student s = new Student();

            Console.WriteLine(h.Name);
            Console.WriteLine(s.Name + " class: " + s.Class);
            Console.ReadKey();
        }
    }

    class Human
    {
        private string sName = "Human";

        public virtual string  Name
        {
            get {return sName;}
            set {sName = value;}
        }
    }

    class Student : Human 
    {
        private string sName = "Student";
        private string sClass = "A";

        public override string Name
        { 
            get {return base.Name + "->" + sName;}
            set {sName = value;}
        }

        public string Class
        {
            get { return sClass; }
            set { sName = value; }
        }
    
    }
}