int compare(const Cell* A, const Cell* B)
{
  if(A == NULL) {
    if(B == NULL) return 0;
    else return -1;
  }
  else if(B == NULL) return 1;
  else if(A->item < B->item) return -1
  else if(A->item > B->item) return 1
  else return compare(A->next, B->next);
}