Was a film 's writer employed by M0 , employed by M1 , M2 , and M3 , and employed by M4
SELECT count(*) WHERE {
?x0 ns:film.writer.film ?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 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M4 .
?x1 a ns:film.film
}