A customer performs a full backup on the first Sunday of the month followed by a cumulative backup on the other Sundays. They also perform an incremental backup each day Monday through Saturday. Tapes are sent off-site for disaster recovery every morning at 10 a.m. The customer experiences a system crash on the Wednesday of the third week at 3 p.m., requiring a system recovery. How many days worth of tapes need to be retrieved to perform a recovery?