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)));