Which ontology has the most classes?
SELECT ?ont ?ont_label
WHERE {
  orkgr:R8342 orkgp:compareContribution ?cont.
  ?cont orkgp:P7034 ?ont.
  ?ont orkgp:P7038 ?cls_cnt;
       rdfs:label ?ont_label.
}
ORDER BY DESC(MAX(xsd:int(?cls_cnt)))
LIMIT 1