what is the unit of length that starts with 'y' and that measures the physical quantity in length.
SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q1978718 . ?sbj wdt:P111 wd:Q36253 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'y')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
unit of length: Q1978718 length: Q36253