Tell me the revised of mccune reischauer of yŏn (s) ryŏn (n)
CREATE TABLE "notes" (
  "hangul" text,
  "hanja" text,
  "revised" text,
  "mc_cune_reischauer" text,
  "estimated_distribution_2000" real
);
SELECT "revised" FROM "notes" WHERE "mc_cune_reischauer"='yŏn (s) ryŏn (n)';