question: Did M4 , M6 , and M7 star M5 and star a Canadian screenwriter that M1 and M2 employed
query: SELECT count(*) WHERE {
  ?x0 a ns:film.writer .
  ?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.nationality ns:m.0d060g .
  M4 ns:film.film.starring/ns:film.performance.actor ?x0 .
  M4 ns:film.film.starring/ns:film.performance.actor M5 .
  M6 ns:film.film.starring/ns:film.performance.actor ?x0 .
  M6 ns:film.film.starring/ns:film.performance.actor M5 .
  M7 ns:film.film.starring/ns:film.performance.actor ?x0 .
  M7 ns:film.film.starring/ns:film.performance.actor M5
  }