Were M1 , M2 , and M3 founded by a film 's art director
SELECT count(*) WHERE {
?x0 ns:film.film_art_director.films_art_directed ?x1 .
?x1 a ns:film.film .
M1 ns:organization.organization.founders ?x0 .
M2 ns:organization.organization.founders ?x0 .
M3 ns:organization.organization.founders ?x0
}