With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: PlayStation 4 is developed by a video game company.
text_B: The Socilor River is a tributary of the Valea Mica River in Romania .. Romania. Romania. Valea Mica. Valea Mica River ( Strei ). tributary. tributary. Valea Mica River. Valea Mica River ( Strei )
not_related.