query: #top 50 for P31 and P279 of items using P156
  SELECT ?class ?classLabel ?count ?use_as_Label
  {	{	SELECT ?class (COUNT(*) AS ?count) (wd:P31 as ?use_as_)
  		{	?a	wdt:P156	?p	; wdt:P31	?class}
          GROUP BY ?class ORDER BY DESC(?count) LIMIT 50
    	}
    	UNION
  	{	SELECT ?class (COUNT(*) AS ?count) (wd:P279 as ?use_as_)
  		{	?a	wdt:P156	?p	; wdt:P279	?class}
          GROUP BY ?class ORDER BY DESC(?count) LIMIT 50
    	}
    	SERVICE wikibase:label { bd:serviceParam wikibase:language "ru,en" }
  }
  ORDER BY DESC(?count) ?class