question: Did a art director 's employer employ M0 and M1 and employ M2 and M3
query: SELECT count(*) WHERE {
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person ?x1 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M0 .
  ?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 .
  ?x1 a ns:film.film_art_director
  }