With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Tramadol may cause constipation.
text_B: Ruzena Slemrova , nee Ruzena Machova -LRB- 10 November 1886 -- 24 August 1962 -RRB- was a Czechoslovak film actress .. She appeared in 77 films between 1914 and 1956 .
not_related.