Did M4 employ M5 , employ a film director that M1 , M2 , and M3 employed , and employ M6
SELECT count(*) WHERE {
?x0 a ns:film.director .
?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 .
M4 ns:business.employer.employees/ns:business.employment_tenure.person ?x0 .
M4 ns:business.employer.employees/ns:business.employment_tenure.person M5 .
M4 ns:business.employer.employees/ns:business.employment_tenure.person M6
}