Was M0 a Mexican film producer that M2 , M3 , and M4 employed
SELECT count(*) WHERE {
M0 a ns:film.producer .
M0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
M0 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
M0 ns:people.person.employment_history/ns:business.employment_tenure.company M4 .
M0 ns:people.person.nationality ns:m.0b90_r
}