query: SELECT ?item ?nomLabel (SUBSTR(?nomLabel,1,1) AS ?letter) WHERE
  {
    ?item wdt:P91 ?orientation .
    ?item wdt:P734 ?nom .
    FILTER( ?orientation in (wd:Q271534, wd:Q43200)) .
      SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }  
  
  }