For each classroom with at least 2 classes, how many classes are offered?
return classrooms ;return classes offered in #1 ;return number of #2 for each #1 ;return #1 where  #3 is  at least 2 ;return classes offered in #4 ;return number of #5 for each #4
['select', 'project', 'group', 'comparative', 'project', 'group']