Was a film 's prequel executive produced by and written by M1 's director , writer , and producer
SELECT count(*) WHERE {
?x0 ns:film.film.executive_produced_by ?x1 .
?x0 ns:film.film.sequel ?x2 .
?x0 ns:film.film.written_by ?x1 .
?x1 ns:film.director.film M1 .
?x1 ns:film.producer.film|ns:film.production_company.films M1 .
?x1 ns:film.writer.film M1 .
?x2 a ns:film.film
}