Who was a film director that M1 and M2 starred and M3 and M4 were directed by
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:film.actor.film/ns:film.performance.film M1 .
?x0 ns:film.actor.film/ns:film.performance.film M2 .
?x0 ns:film.director.film M3 .
?x0 ns:film.director.film M4
}