With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Robert Browning was only a novelist.
text_B: Streptomyces graminearus is a bacterium species from the genus of Streptomyces .. Streptomyces. Streptomyces. Streptomyces graminearus produces the antibiotic gougerotin .. Streptomyces. Streptomyces. antibiotic. antibiotic. gougerotin. gougerotin
not_related.