Which isotope of lead has the least mass excess which decays to thallium-185?
select ?ent where { ?ent wdt:P31 wd:Q1372384 . ?ent wdt:P2160 ?obj . ?ent wdt:P816 wd:Q18883276} ORDER BY ASC(?obj)LIMIT 5 
isotope of lead: Q1372384 thallium-185: Q18883276