using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("aaaaa") ;

    }

​

}

​

​

/**

 * Definition for a binary tree node. */

public class TreeNode {

      public int val;

      public TreeNode left;

      public TreeNode right;

      public TreeNode(int x) { val = x; }

}

​

public class Solution {

    public int MaxDepth(TreeNode root) {

        if(root == null)

            return 0;

        int l = 0,r = 0 ;

        if(root.left != null)

            l = MaxDepth(root.left) ;

        if(root.right != null)

            r = MaxDepth(root.right) ;

        if(l>r)

            return 1 + l ;

        else

            return 1 + r ;

    }

}