class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right
def op(root, val):
    if root is None:
        return TreeNode(val)
    if val < root.val:
        root.left = op(root.left, val)
    else:
        root.right = op(root.right, val)
    return root