Did M2 's prequel 's prequel star M0 and star M1
SELECT count(*) WHERE {
?x0 ns:film.film.sequel ?x1 .
?x0 ns:film.film.starring/ns:film.performance.actor M0 .
?x0 ns:film.film.starring/ns:film.performance.actor M1 .
?x1 ns:film.film.sequel M2
}