With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Brock Lesnar signed with Hero's, a Japanese mixed martial arts promotion.
text_B: Chile competed at the 2012 Summer Paralympics in London , United Kingdom from August 29 to September 9 , 2012 .. London. London. Chile. Chile. 2012 Summer Paralympics. 2012 Summer Paralympics. Chile won its first medal at this event .. Chile. Chile
not_related.