If an image contains at least one person behind a dead water buffalo.
return water buffalo ;return #1 that is  dead ;return people ;return #3 behind #2 ;return images of  #4 ;return number of #4 for each #5 ;return #5 where #6 is  at least one ;return number of #7 ;return if  #8 is  equal to one
['select', 'filter', 'select', 'filter', 'project', 'group', 'comparative', 'aggregate', 'boolean']