With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Black Sails is a prequel.
text_B: Radomir Halfar is a former Czechoslovak slalom canoeist who competed in the 1970s .. Czechoslovak. Czechoslovakia. slalom canoeist. whitewater slalom. He won two medals in the C-2 team event at the ICF Canoe Slalom World Championships with a gold in 1977 and a silver in 1975 .. ICF Canoe Slalom World Championships. ICF Canoe Slalom World Championships. 1977 ICF Canoe Slalom World Championships. 1975 ICF Canoe Slalom World Championships
not_related.