Find the first names of professors who are not playing Canoeing or Kayaking.
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'