Did M2 edit a film 's sequel and write M1 's prequel
SELECT count(*) WHERE {
?x0 ns:film.film.prequel ?x1 .
?x1 a ns:film.film .
?x2 ns:film.film.sequel M1 .
M2 ns:film.editor.film ?x0 .
M2 ns:film.writer.film ?x2
}