question: If an image contains at least one person behind a dead water buffalo.
#1 return water buffalo 
#2 return #1 that is  dead 
#3 return people 
#4 return #3 behind #2 
#5 return images of  #4 
#6 return number of #4 for each #5 
#7 return #5 where #6 is  at least one 
#8 return number of #7 
#9 return if  #8 is  equal to one