How many events did not get any bronze medals?
return events ;return bronze medals of #1 ;return number of  #2 for each #1 ;return #1 where #3 is at least one ;return number of  #1 ;return number of  #4 ;return the  difference of #5 and  #6
['select', 'project', 'group', 'comparative', 'aggregate', 'aggregate', 'arithmetic']