static LinkedListNode removeMid(LinkedListNode n) {
        LinkedListNode fast, slow;
        fast = n;
        slow = n;

        while (fast != null && fast.next != null) {
            fast = fast.next.next;
            slow = slow.next;
        }

        slow.v = slow.next.v;
        slow.next = slow.next.next;

        return n;
    }