Find Median in BST

Create a program that reads a Binary Search Tree (BST) and computes the median value of all its nodes. The input consists of a list of integers representing the pre-order traversal of the BST, with '-1' representing a null node. The median is defined as the middle value when the nodes are sorted. If the number of nodes is even, return the average of the two middle values. Output the median. Example Input: 7 3 -1 -1 9 -1 -1 5 -1 -1 Example Output: 5