Return the names of countries that have players that play the Forward position, as well as players who play the Defender position.
return countries ;return players of  #1 ;return positions of  #2 ;return #1 where #3 is  Forward ;return #1 where #3 is  Defender ;return #1 of  both #4 and  #5 ;return names of  #6
['select', 'project', 'project', 'comparative', 'comparative', 'intersection', 'project']