How many people had filled a role in the episode titled "Cherished", but did not show up in the on-screen credits?
titled "Cherished" refers to title = 'Cherished'; did not show up in the on-screen credits refers to credited = ''
SELECT COUNT(T1.episode_id) FROM Episode AS T1 INNER JOIN Credit AS T2 ON T1.episode_id = T2.episode_id WHERE T1.title = 'Cherished' AND T2.credited = 'false'