What association football league's name starts with "S"?
SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q15991303 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 's')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
association football league: Q15991303