What are the names of countries that have both players with position forward and players with position defender?
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']