of the gray items shown, how many are made of the same material as the blue sphere?
return the  blue sphere ;return items shown ;return #2 that are gray ;return material of #1 ;return materials of #3 ;return #3 where #5 is the  same as #4 ;return number of  #6
['select', 'select', 'filter', 'project', 'project', 'comparative', 'aggregate']