Did a film distributor employ M1 , employ a screenwriter , employ M2 and M3 , and employ M4
SELECT count(*) WHERE {
?x0 a ns:film.film_distributor .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person ?x1 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M1 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M2 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M3 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M4 .
?x1 a ns:film.writer
}