Was M3 's editor a art director that directed and wrote M1 and M2
SELECT count(*) WHERE {
?x0 a ns:film.film_art_director .
?x0 ns:film.director.film M1 .
?x0 ns:film.director.film M2 .
?x0 ns:film.editor.film M3 .
?x0 ns:film.writer.film M1 .
?x0 ns:film.writer.film M2
}