With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Bill Black is noted as one of the pioneers of rock and roll music.
text_B: Njivak -LRB- Cyrillic  : Њивак -RRB- is a village in the municipality of Gradacac , Bosnia and Herzegovina .. Gradacac. Gradacac. Cyrillic. Cyrillic. village. village. municipality. Municipalities of Bosnia and Herzegovina. Bosnia and Herzegovina. Bosnia and Herzegovina
not_related.