With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Roger Federer coaches a racket sport.
text_B: A laboratory -LRB- CommE -LSB- ləˈbɒrətri -RSB- or -LSB- ləˈbɒrətəri -RSB- , AmE -LSB- ˈlæbərətɔri -RSB- informally , lab -RRB- is a facility that provides controlled conditions in which scientific or technological research , experiments , and measurement may be performed .. scientific. science. measurement. measurement
not_related.