Did M3 executive produce a film whose executive producer executive produced M1 and M2
SELECT count(*) WHERE {
?x0 a ns:film.film .
?x0 ns:film.film.executive_produced_by ?x1 .
?x1 ns:film.producer.films_executive_produced M1 .
?x1 ns:film.producer.films_executive_produced M2 .
M3 ns:film.producer.films_executive_produced ?x0
}