public static Node insert(Node root,int data) {
        root = addRecursive(root, data);
        return root;
    }
    
    public static Node addRecursive(Node current, int data) {
        if(current == null) return new Node(data);
        else {
            if(current.data < data) {
                current.right = addRecursive(current.right, data);
            }
            if(current.data > data) {
                current.left = addRecursive(current.left, data);
            }
        }
        return current;
    }