Was a costume designer 's employer M1 's prequel 's producer
SELECT count(*) WHERE {
?x0 ns:business.employer.employees/ns:business.employment_tenure.person ?x1 .
?x0 ns:film.producer.film|ns:film.production_company.films ?x2 .
?x1 a ns:film.film_costumer_designer .
?x2 ns:film.film.sequel M1
}