question: Did M1 and M2 distribute a prequel of M0
query: SELECT count(*) WHERE {
  ?x0 ns:film.film.sequel M0 .
  M1 ns:film.film_distributor.films_distributed/ns:film.film_film_distributor_relationship.film ?x0 .
  M2 ns:film.film_distributor.films_distributed/ns:film.film_film_distributor_relationship.film ?x0
  }