question: Show the customer id and number of accounts with most accounts.
#1 return customers 
#2 return accounts  of #1 
#3 return number of #2 for each #1 
#4 return #1 where #3 is  highest 
#5 return customer id of #4 
#6 return accounts  of #4 
#7 return number of #6 
#8 return #5 , #7