question: Was a American star of M1 M2 's art director
query: SELECT count(*) WHERE {
  ?x0 ns:film.actor.film/ns:film.performance.film M1 .
  ?x0 ns:film.film_art_director.films_art_directed M2 .
  ?x0 ns:people.person.nationality ns:m.09c7w0
  }