CREATE TABLE table_1577 ("Constituency" TEXT, "Electorate" FLOAT, "Votes" FLOAT, "Turnout" TEXT, "Yes" FLOAT, "No" FLOAT, "Spoilt" FLOAT, "Percent Yes" TEXT)

Name the least yes for dublin south
SELECT MIN("Yes") FROM table_1577 WHERE "Constituency" = 'Dublin South'
SELECT MIN("Yes") FROM "table_1577" WHERE "Constituency" = 'Dublin South'