using System;

​

public class Program

{

    public int totalLenght = 0;

    public static void Main()

    {

        // here's a maze data, starting with a wall that has left and right walls connected to it

        Wall maze = new(20) {

          Left = new(23) {

            Left = new(12) {

              Left = new(15),

              Right = new(3)

            },

            Right = new(45) {

              Left = new(24) {

                Left = new(4),

                Right = new(7)

              },

              Right = new(32)

            }

          },

          Right = new(24)

        };

        // compute the total length of the walls of the maze

        // Expected output: 209

        Console.WriteLine(GetLength(maze));

    }

    // computes the length of the provided wall + the length of its left and right siblings

    public static int GetLength(Wall wall) {

        // TODO

        //if wall.left!=null

        //GetLength(wall.left)

        //totalLength += wall.Length'

        if ( wall.Left != null){

            GetLength(wall.Left);

            totalLenght += wall.Length;

        }

    }

}

​

public class Wall {

    public Wall Left;

    public Wall Right;

    public int Length;

    public Wall(int length) { this.Length = length; }

}

​