Find the id and city of the student address with the highest average monthly rental.
return student addresses ;return monthly rentals of  #1 ;return average of  #2 for each #1 ;return #1 where  #3 is  highest ;return id of  #4 ;return city of  #4 ;return #5 ,   #6
['select', 'project', 'group', 'superlative', 'project', 'project', 'union']