Was a film written by M1 and M2 and written by M3 and M4
SELECT count(*) WHERE {
?x0 a ns:film.film .
?x0 ns:film.film.written_by M1 .
?x0 ns:film.film.written_by M2 .
?x0 ns:film.film.written_by M3 .
?x0 ns:film.film.written_by M4
}