With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Mark Wahlberg has an early career as frontman for a musical group.
text_B: The Irish League in season 1999 -- 2000 comprised two divisions of 10 teams each , and Linfield won the championship .. Linfield. Linfield F.C.. Irish League. IFA Premiership
not_related.