What is the name of the party that starts with y and occurs on the day of the winter solstice?
SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q200538 . ?sbj wdt:P837 wd:Q207932 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'y')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
party: Q200538 winter solstice: Q207932