Was a actor of M1 , M2 , and M3 a screenwriter
SELECT count(*) WHERE {
?x0 a ns:film.writer .
?x0 ns:film.actor.film/ns:film.performance.character M1 .
?x0 ns:film.actor.film/ns:film.performance.character M2 .
?x0 ns:film.actor.film/ns:film.performance.character M3
}