question: Which company that M1 acquired and was acquired by acquired M2 and M3
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:business.employer .
  ?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M1 .
  ?x0 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M1 .
  ?x0 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M2 .
  ?x0 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M3
  }