If there are three birds sitting on a person,  one on each arm and one on their shoulder.
return birds ;return person ;return arms of #2 ;return #1 sitting on   #3 ;return number of  #4 for each  #3 ;return #3 where  #5 is equal to  one ;return number of  #6 ;return if  #7 is equal to  two ;return shoulders of #2 ;return #1 sitting on   #9 ;return number of  #10 ;return if  #11 is equal to  one ;return if  both  #8 and #12 are true
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