Given a binary tree `root`, a node X in the tree is named good if in the path from root to X there are no nodes with a value greater than X.

Return the number of good nodes in the binary tree.

Example 1:

    Input: root = [3,1,4,3,null,1,5]

    Output: 4

    Explanation: Nodes in blue are good.

    Root Node (3) is always a good node.

    Node 4 -> (3,4) is the maximum value in the path starting from the root.

    Node 5 -> (3,4,5) is the maximum value in the path

    Node 3 -> (3,1,3) is the maximum value in the path.

Example 2:

    Input: root = [3,3,null,4,2]

    Output: 3

    Explanation: Node 2 -> (3, 3, 2) is not good, because "3" is higher than it.

Example 3:

    Input: root = [1]

    Output: 1

    Explanation: Root is considered as good.

Constraints:

- The number of nodes in the binary tree is in the range `[1, 10^5]`.
- Each node's value is between `[-10^4, 10^4]`.