Did M1 star M2 , star M3 , and star a star of M0
SELECT count(*) WHERE {
?x0 ns:film.actor.film/ns:film.performance.film M0 .
M1 ns:film.film.starring/ns:film.performance.actor ?x0 .
M1 ns:film.film.starring/ns:film.performance.actor M2 .
M1 ns:film.film.starring/ns:film.performance.actor M3
}