Finding 10 Most Recent Missions

What i have is table with:

mission_id, mission_type_id, security_level and code_name.

What i have to do is get the 10 most recent missions and change their security level to the highest one in their mission_type_id but ONLY if code_name length is >7

So far I have this, the problem is that the oracle moans about the order and wants me to close the bracket before the order

sql

UPDATE missions m
SET m.security_level = (
SELECT max(m2.security_level)
FROM missions m2
WHERE m2.mission_type_id = m.mission_type_id
AND length(m2.code_name) > 7
)
WHERE m.mission_ID IN (
Select m3.mission_id
From missions m3
ORDER BY m3.mission_id desc)