Were M4 , M5 , and M6 directed by a cinematographer employed by M1 and M2 and employed by M3
SELECT count(*) WHERE {
?x0 a ns:film.cinematographer .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
M4 ns:film.film.directed_by ?x0 .
M5 ns:film.film.directed_by ?x0 .
M6 ns:film.film.directed_by ?x0
}