question: Was a country of nationality of a employee of M0 and M1 M2
query: SELECT count(*) WHERE {
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M0 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  M2 ^ns:people.person.nationality ?x0
  }