Was a employer of M0 and M1 acquired by M2 , acquired by M3 , and acquired by M4 , M5 , and M6
SELECT count(*) WHERE {
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M0 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M1 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M2 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M3 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M4 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M5 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M6
}