question: Did M1 acquire a person 's employer , acquire M2 and M3 , and acquire M4
query: SELECT count(*) WHERE {
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person ?x1 .
  ?x1 a ns:people.person .
  M1 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired ?x0 .
  M1 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M2 .
  M1 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M3 .
  M1 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M4
  }