query: SELECT ?teacher ?teacherLabel ?count
  WHERE
  {
    {
      SELECT ?teacher (COUNT(DISTINCT ?student) AS ?count)
      WHERE
      {
        ?teacher wdt:P802|^wdt:P1066 ?student.
      }
      GROUP BY ?teacher
      HAVING(?count > 1)
    }
    SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
  }
  ORDER BY DESC(?count)