Task: Question Generation
Input (English): #1 return students 
#2 return courses  that  #1 registered  
#3 return number of  #2 for each #1 
#4 return #1 where #3 is  at least one 
#5 return courses  that  #4 registered  
#6 return number of  #5 for each #4 
#7 return ids of #4 
#8 return #7 ,  #6
Output (English): List the id of students who registered some courses and the number of their registered courses?