Who distributed a prequel of M1 's prequel
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:film.film_distributor.films_distributed/ns:film.film_film_distributor_relationship.film ?x1 .
?x1 ns:film.film.sequel ?x2 .
?x2 ns:film.film.sequel M1
}