Did a film 's editor and writer edit M0 and edit M1
SELECT count(*) WHERE {
?x0 ns:film.editor.film ?x1 .
?x0 ns:film.editor.film M0 .
?x0 ns:film.editor.film M1 .
?x0 ns:film.writer.film ?x1 .
?x1 a ns:film.film
}