Update readme.md

Author: sushant097

coding_solutions/DataStructure_related/Tree/Readme.md

@@ -4,7 +4,7 @@
 | :----: | :-----------------------------: | :----: |
 | 1 | [Maximum Depth of Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/)| [python3](https://github.com/sushant097/Data-Structure-Algorithms-Collections-Python/blob/master/coding_solutions/DataStructure_related/Tree/MaxDepthTree.py) |
 | 2 | [Check Validity of BST](https://leetcode.com/problems/validate-binary-search-tree/)| [python3](https://github.com/sushant097/Data-Structure-Algorithms-Collections-Python/blob/master/coding_solutions/DataStructure_related/Tree/CheckValidityBST.py) |
-| 2 | [Check Symmetricity of Binary Tree](https://leetcode.com/problems/symmetric-tree/)| [python3](https://github.com/sushant097/Data-Structure-Algorithms-Collections-Python/blob/master/coding_solutions/DataStructure_related/Tree/CheckSymmetryTree.py) |
-| 3 | [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/)| [python3](https://github.com/sushant097/Data-Structure-Algorithms-Collections-Python/blob/master/coding_solutions/DataStructure_related/Tree/BinaryTreeLevelOrderTraversal.py) |
+| 3 | [Check Symmetricity of Binary Tree](https://leetcode.com/problems/symmetric-tree/)| [python3](https://github.com/sushant097/Data-Structure-Algorithms-Collections-Python/blob/master/coding_solutions/DataStructure_related/Tree/CheckSymmetryTree.py) |
+| 4 | [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/)| [python3](https://github.com/sushant097/Data-Structure-Algorithms-Collections-Python/blob/master/coding_solutions/DataStructure_related/Tree/BinaryTreeLevelOrderTraversal.py) |