/**

* Definition for a binary tree node.

* public class TreeNode {

*     int val;

*     TreeNode left;

*     TreeNode right;

*     TreeNode() {}

*     TreeNode(int val) { this.val = val; }

*     TreeNode(int val, TreeNode left, TreeNode right) {

*         this.val = val;

*         this.left = left;

*         this.right = right;

*     }

* }

*/

class Solution {

}