Given the root of a binary search tree and a target value, return the value in the BST that is closest to the target. If there are multiple answers, print the smallest.

 

Example 1:

Input: root = [4,2,5,1,3], target = 3.714286
Output: 4

Example 2:

Input: root = [1], target = 4.428571
Output: 1

 

Constraints:

• The number of nodes in the tree is in the range [1, 104].
• 0 <= Node.val <= 109
• -109 <= target <= 109