Question: Find the first names of professors who are not playing Canoeing or Kayaking.
SQL: SELECT fname FROM faculty WHERE rank  =  'Professor' EXCEPT SELECT DISTINCT T1.fname FROM Faculty AS T1 JOIN Faculty_participates_in AS T2 ON T1.facID  =  T2.facID JOIN activity AS T3 ON T2.actid  =  T2.actid WHERE T3.activity_name  =  'Canoeing' OR T3.activity_name  =  'Kayaking'