Was a film producer employed by M1 , employed by M4 's distributor , employed by M2 , and employed by M3
SELECT count(*) WHERE {
?x0 a ns:film.producer .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
?x1 ns:film.film_distributor.films_distributed/ns:film.film_film_distributor_relationship.film M4
}