Show names of musicals which have at least three actors.
SELECT T2.Name FROM actor AS T1 JOIN musical AS T2 ON T1.Musical_ID  =  T2.Musical_ID GROUP BY T1.Musical_ID HAVING COUNT(*)  >=  3
SELECT T2.Name FROM actor AS T1 JOIN musical AS T2 ON T1.Musical_ID  =  T2.Musical_ID GROUP BY T1.Musical_ID HAVING COUNT(*)  >=  3
[{'Name': 'The Book of Mormon'}]