question: Which Advisor has most of students? List advisor and the number of students.
#1 return advisors 
#2 return students  of  #1 
#3 return number of  #2 for each  #1 
#4 return #1 where #3 is  highest 
#5 return students  of  #4 
#6 return number of  #5 
#7 return #4 ,  #6