Was a art director of M1 , M2 , M3 , and M4 a actor
SELECT count(*) WHERE {
?x0 a ns:film.actor .
?x0 ns:film.film_art_director.films_art_directed M1 .
?x0 ns:film.film_art_director.films_art_directed M2 .
?x0 ns:film.film_art_director.films_art_directed M3 .
?x0 ns:film.film_art_director.films_art_directed M4
}