Were M2 and M3 edited by a film director and edited by a art director
SELECT count(*) WHERE {
?x0 a ns:film.film_art_director .
?x1 a ns:film.director .
M2 ns:film.film.edited_by ?x0 .
M2 ns:film.film.edited_by ?x1 .
M3 ns:film.film.edited_by ?x0 .
M3 ns:film.film.edited_by ?x1
}