class TreeNode:
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None

def insertNode(root, x):
    if not root:
        return TreeNode(x)

    if x < root.val:
        root.right = insertNode(root.right, x)
    else:
        root.left = insertNode(root.left, x)

    return root