# -*- coding:utf-8 -*-

# class TreeNode:

#     def __init__(self, x):

#         self.val = x

#         self.left = None

#         self.right = None

class Solution:

    # 返回镜像树的根节点

    def Mirror(self, root):

        # write code here

        return self.swap(root)

    def swap(self,tree):

        if not tree:

            return

        temp = tree.left

        tree.left = self.swap(tree.right)

        tree.right = self.swap(temp)

        return tree