question: Did M2 employ M1 's employee , employ M3 and M4 , and employ M0 's employee
query: SELECT count(*) WHERE {
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M0 .
  ?x1 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  M2 ns:business.employer.employees/ns:business.employment_tenure.person ?x0 .
  M2 ns:business.employer.employees/ns:business.employment_tenure.person ?x1 .
  M2 ns:business.employer.employees/ns:business.employment_tenure.person M3 .
  M2 ns:business.employer.employees/ns:business.employment_tenure.person M4
  }