Did M3 employ M4 and M5 , employ a Canadian writer of M0 and M1 , and employ M6
SELECT count(*) WHERE {
?x0 ns:film.writer.film M0 .
?x0 ns:film.writer.film M1 .
?x0 ns:people.person.nationality ns:m.0d060g .
M3 ns:business.employer.employees/ns:business.employment_tenure.person ?x0 .
M3 ns:business.employer.employees/ns:business.employment_tenure.person M4 .
M3 ns:business.employer.employees/ns:business.employment_tenure.person M5 .
M3 ns:business.employer.employees/ns:business.employment_tenure.person M6
}