With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: The Flash is based on a Marvel Comics character.
text_B: Stefan Racovita was Prince of Wallachia , Romania , between 8 February 1764 and 29 August 1765 .. Prince. List of rulers of Wallachia. Wallachia. Wallachia. Romania. Romania
not_related.