With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Earth has never suffered a mass extinction.
text_B: Krzysztof Stelmach -LRB- born 11 November 1967 -RRB- is a former Polish volleyball player , a member of Poland men 's national volleyball team in 1987 -- 1997 and coach assistant of Polish club PGE Skra Bełchatow , a participant of the 1996 Olympic Games , four-time Polish Champion -LRB- 1990 , 2006 , 2007 , 2008 -RRB- .. Polish. Poland. Poland. Poland. Skra Bełchatow. Skra Bełchatow. PGE Skra Bełchatow. PGE Skra Bełchatow. volleyball player. volleyball player. 1996 Olympic Games. Volleyball at the 1996 Summer Olympics – Men's tournament. Polish Champion. PlusLiga. 2005–06 PlusLiga. 2006–07 PlusLiga. 2007–08 PlusLiga
not_related.