question: If there are only two dogs pulling one of the sleds.
#1 return dogs 
#2 return sleds 
#3 return #1 that are  pulling #2 
#4 return number of #3 for each #2 
#5 return #2 where #4 is  equal to two 
#6 return number of #5 
#7 return If #5 is  equal to one