Did M3 and M4 employ a film producer that M1 starred and M2 starred
SELECT count(*) WHERE {
?x0 a ns:film.producer .
?x0 ns:film.actor.film/ns:film.performance.film M1 .
?x0 ns:film.actor.film/ns:film.performance.film M2 .
M3 ns:business.employer.employees/ns:business.employment_tenure.person ?x0 .
M4 ns:business.employer.employees/ns:business.employment_tenure.person ?x0
}