Count me the number of people whose military unit is involved with Close air support?
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/property/role> <http://dbpedia.org/resource/Close_air_support> . ?uri <http://dbpedia.org/ontology/militaryUnit> ?x  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/MilitaryPerson>}
Close_air_support