return me the number of papers written by " H. V. Jagadish " and " Divesh Srivastava " . 
return papers ;return #1 written by H. V. Jagadish ;return #1 written by Divesh Srivastava ;return #1 of  both #2 and  #3 ;return number of  #4
['select', 'filter', 'filter', 'intersection', 'aggregate']