With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Ayn Rand was not an advocate of collectivist ideology.
text_B: The Ciupari River is a tributary of the Sadu River in Romania .. Romania. Romania. Sadu. Sadu River ( Olt ). tributary. tributary. Sadu River. Sadu River ( Olt )
not_related.