SELECT T2.f1 FROM user_profiles AS T1 JOIN follows AS T2 ON T1.uid  =  T2.f2 WHERE T1.name  =  "Mary" INTERSECT SELECT T2.f1 FROM user_profiles AS T1 JOIN follows AS T2 ON T1.uid  =  T2.f2 WHERE T1.name  =  "Susan"
Find the id of users who are followed by Mary and Susan.
[Schema (values) (types)]: | twitter_1 |  follows : f1 (text) , f2 (number) | tweets : id (text) , uid (number) , text (number) , createdate (number) | user_profiles : uid (text) , name (number) , email (number) , partitionid (number) , followers (number);