How long is the total lesson time taught by staff with first name as Janessa and last name as Sawayn?
return staff ;return first name  of  #1 ;return last name  of  #1 ;return #1 where  #2 is  Janessa ;return #1 where  #3 is  Sawayn ;return #1 of  both #4 and #5 ;return lesson times of  #6 ;return sum of  #7
['select', 'project', 'project', 'comparative', 'comparative', 'intersection', 'project', 'aggregate']