question: Were M2 and M4 acquired by M3 and acquired by a employer of M0 and M1
query: 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 .
  M2 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company ?x0 .
  M2 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M3 .
  M4 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company ?x0 .
  M4 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M3
  }