static boolean compareLists(SinglyLinkedListNode head1, SinglyLinkedListNode head2) {
        while(head1!=null || head2!=null){
            if(head1 == null || head2==null){
                return false;
            }
            if(head1.data == head2.data){
                head1 = head1.next;
                head2 = head2.next;
            }else{
                return false;
            }
        }
        return true;
    }