Was a screenwriter a Mexican person that M2 was directed by and written by
SELECT count(*) WHERE {
?x0 a ns:film.writer .
?x0 a ns:people.person .
?x0 ns:film.director.film M2 .
?x0 ns:film.writer.film M2 .
?x0 ns:people.person.nationality ns:m.0b90_r
}