using System;

​

public class Node

    {

        public int val;

        public Node r;

        public Node l;

        public Node(int val, Node r, Node l)

            { this.val=val;

             this.r=r;

             this.l=l;

            }

    }

public class Program

{

    public static void Main()

    {

        Node head = new Node(10, new Node(30,new Node(40,null,null),new Node(15,new Node(11,null,null),new Node(20,null,null)), new Node(5,new Node(7,),new Node(3)));

    }

}