Was M1 a film that a distributor of M0 distributed
SELECT count(*) WHERE {
?x0 ns:film.film_distributor.films_distributed/ns:film.film_film_distributor_relationship.film M0 .
M1 a ns:film.film .
M1 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor ?x0
}