Was a American director of M3 and M4 employed by M0 and M1
SELECT count(*) WHERE {
?x0 ns:film.director.film M3 .
?x0 ns:film.director.film M4 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M0 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
?x0 ns:people.person.nationality ns:m.09c7w0
}