Were M2 and M4 directed by a film producer , directed by M1 's writer , and directed by M3
SELECT count(*) WHERE {
?x0 a ns:film.producer .
?x1 ns:film.writer.film M1 .
M2 ns:film.film.directed_by ?x0 .
M2 ns:film.film.directed_by ?x1 .
M2 ns:film.film.directed_by M3 .
M4 ns:film.film.directed_by ?x0 .
M4 ns:film.film.directed_by ?x1 .
M4 ns:film.film.directed_by M3
}