Was a film 's sequel 's sequel 's writer M0 's writer
SELECT count(*) WHERE {
?x0 ns:film.writer.film ?x1 .
?x0 ns:film.writer.film M0 .
?x1 ns:film.film.prequel ?x2 .
?x2 ns:film.film.prequel ?x3 .
?x3 a ns:film.film
}