Was a prequel of a film edited by and written by M1 's director
SELECT count(*) WHERE {
?x0 ns:film.film.edited_by ?x1 .
?x0 ns:film.film.sequel ?x2 .
?x0 ns:film.film.written_by ?x1 .
?x1 ns:film.director.film M1 .
?x2 a ns:film.film
}