using System;

public class Program

{

    public static void Main()

    {

        Demo.CallAction1(null);

    }

    public class Demo

    {

        public void DemoAction1() {}

        public void DemoAction2() {}

        public static void Execute(Action a) { a();}

        public static void CallAction1(Demo d)  { Execute(d.DemoAction1); }

    }

}