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

namespace ConsoleApplication1
{
    public delegate int BinaryOp(int x, int y);

    public class MyMath
    {
        public int Addition(int x, int y)
        {
            return x + y;
        }
        public int Subtraction(int x, int y)
        {
            return x - y;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            MyMath mm = new MyMath();
            BinaryOp bo = mm.Addition;
            BinaryOp bo1 = mm.Subtraction;
            BinaryOp all = bo;
            all -= bo1;

            Console.WriteLine("{0}", all(14, 40));
        }
    }
}