Was M2 's star employed by M0 , employed by a film producer , and employed by M1
SELECT count(*) WHERE {
?x0 ns:film.actor.film/ns:film.performance.film M2 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M0 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
?x1 a ns:film.producer
}