Were M2 and M3 written by a screenwriter and edited by a star and editor of M1
SELECT count(*) WHERE {
?x0 a ns:film.writer .
?x1 ns:film.actor.film/ns:film.performance.film M1 .
?x1 ns:film.editor.film M1 .
M2 ns:film.film.edited_by ?x1 .
M2 ns:film.film.written_by ?x0 .
M3 ns:film.film.edited_by ?x1 .
M3 ns:film.film.written_by ?x0
}