PREFIX rdf:     <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs:    <http://www.w3.org/2000/01/rdf-schema#>
PREFIX :        <http://example/>

SELECT ?X ?Y
WHERE {
	?X rdfs:subClassOf ?Y
    FILTER (?X != ?Y )
    FILTER regex(str(?X), "^http://example/")
 	OPTIONAL {
 	  ?X rdfs:subClassOf ?Y2 . ?Y2 rdfs:subClassOf ?Y
      FILTER (?X != ?Y2 && ?Y2 != ?Y)
         }.
 	FILTER (!bound(?Y2))
}