using System;
namespace Ref
{
    class Program
    {
        static void Main(string[] args)
        {
            SayHello obj = new SayHello();
            Type type = typeof(SayHello);
            type.GetMethod("Say").Invoke(obj, new object[0]);
            Console.ReadKey(true);
        }
    }

    class SayHello
    {
        public void Say()
        {
            Console.WriteLine("Hello World!");
        }
    }
}