Given a binary search tree, return its height—that is, the maximum depth reached by the tree.

Example: given a BST with a single node, your function would return 0.

Given a linear BST with only right side nodes 0 -> 1 -> 2 -> (null), where 2 is the tail, your function would return a max height of 2.

Hint: BSTs are a recursively defined data structure.

Hint #2: which tree traversal method covered in the traversal lecture might come in handy here?