question: Was a company founded by M1 acquired by M2 and M3 and acquired by M4
query: SELECT count(*) WHERE {
  ?x0 a ns:business.employer .
  ?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.founders M1
  }