With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Christine Daaé is a protagonist.
text_B: Christine Daae is a fictional character and the female protagonist of Gaston Leroux 's 1910 novel The Phantom of the Opera and of the various adaptations of the work .. The Phantom of the Opera. The Phantom of the Opera. Gaston Leroux. Gaston Leroux. fictional character. Character ( arts ). protagonist. protagonist. Erik , the Phantom of the Opera falls in love with her .
related.