With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Heidi Klum has acted four times.
text_B: Left in Dark Times  : A Stand Against the New Barbarism is a 2008 book by Bernard-Henri Levy published on September 16 , 2008 .. Bernard-Henri Levy. Bernard-Henri Levy
not_related.