With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Peter Davison played the protagonist of a British science-fiction show.
text_B: The Fifth Doctor is an incarnation of the Doctor , the protagonist of the BBC science fiction television series Doctor Who .. the Doctor. Doctor ( Doctor Who ). BBC. BBC. science fiction television. Science fiction on television. Doctor Who. Doctor Who. He is portrayed by Peter Davison .. Peter Davison. Peter Davison. Within the series ' narrative , the Doctor is a centuries-old Time Lord alien from the planet Gallifrey who travels in time and space in his TARDIS , frequently with companions .. the Doctor. Doctor ( Doctor Who ). Time Lord. Time Lord. Gallifrey. Gallifrey. travels in time and space. time travel in fiction. TARDIS. TARDIS. companions. companion ( Doctor Who ). When the Doctor is critically injured , he can regenerate his body ; in doing so , his physical appearance and personality change .. the Doctor. Doctor ( Doctor Who ). regenerate. regeneration ( Doctor Who ). Davison portrays the fifth such incarnation , who has a vulnerable side and a tendency towards indecisiveness , dressed as a boyish Edwardian cricketer .. Edwardian. Edwardian era. He travelled with a host of companions , including boy genius Adric -LRB- Matthew Waterhouse -RRB- , alien aristocrat Nyssa -LRB- Sarah Sutton -RRB- and Australian flight attendant Tegan Jovanka -LRB- Janet Fielding -RRB- , whom he had travelled alongside in his previous incarnation .. Adric. Adric. Nyssa. Nyssa ( Doctor Who ). Tegan Jovanka. Tegan Jovanka. companions. companion ( Doctor Who ). Matthew Waterhouse. Matthew Waterhouse. Sarah Sutton. Sarah Sutton. Janet Fielding. Janet Fielding. He also shared later adventures alongside devious schoolboy Vislor Turlough -LRB- Mark Strickson -RRB- and American college student Peri Brown -LRB- Nicola Bryant -RRB- .. Vislor Turlough. Vislor Turlough. Peri Brown. Peri Brown. Mark Strickson. Mark Strickson. Nicola Bryant. Nicola Bryant
related.