// actually upperBound
Node* lowerBound(Node* root, int value)
{
	if (root == nullptr)
		return nullptr;

	if (root->value == value)
		return root;

	if (root->value < value)
		return lowerBound(root->rightNode, value);
	else
	{
		Node* temp = lowerBound(root->leftNode, value);
		if (temp)
			return temp;
		return root;
	}
}

// actually lowerBound
Node* upperBound(Node* root, int value)
{
	if (root == nullptr)
		return nullptr;

	if (root->value == value)
		return root;

	if (root->value > value)
		return upperBound(root->leftNode, value);
	else
	{
		Node* temp = upperBound(root->rightNode, value);
		if (temp)
			return temp;
		return root;
	}
}