question: Show all branch names with the number of members in each branch registered after 2015.
#1 return branch  
#2 return when  #1 registered 
#3 return #1 where #2 is  after 2015 
#4 return members 
#5 return number of  #4 for each #3 
#6 return names of #3 
#7 return #6 ,  #5