Input (grade 13): He first appears in the 2005 Doctor Who episode "The Empty Child" and reappears throughout the remaining episodes of the 2005 series as a companion of the ninth incarnation of the series' protagonist the Doctor.
Output (grade 11): He was first in Doctor Who in the 2005 episode "The Empty Child" and is in the show throughout the rest of the 2005 series as a companion of the Ninth Doctor.