class Program
    {
        public delegate void Del(string message);
        
        public static void DelegateMethod(string message)
        {
            System.Console.WriteLine(message);
        }
        public static void MessageCallBack(int a,int b,Del callback)
        {
            callback("the number is "+(a+b).ToString());
        }
        
        static void Main()
        {
            //Del hander=new Program.Del(DelegateMethod);
            Del hander=DelegateMethod;
            MessageCallBack(1,2,hander);
            Console.ReadKey(true);
        }
    }