Was M0 a Mexican screenwriter that produced M3 and M4
SELECT count(*) WHERE {
M0 a ns:film.writer .
M0 ns:film.producer.film|ns:film.production_company.films M3 .
M0 ns:film.producer.film|ns:film.production_company.films M4 .
M0 ns:people.person.nationality ns:m.0b90_r
}