import qualified Data.Set as S

solve :: [([Int], String)] -> Int
solve = go (S.fromList [0..9])
  where
    go s [] = head $ S.elems s
    go s ((nn,yn):xs)
      | yn == "YES" = go (S.intersection s (S.fromList nn)) xs
      | yn == "NO"  = go (S.difference s (S.fromList nn)) xs

main :: IO ()
main = do
    n <- readLn :: IO Int
    ll <- map words . lines <$> getContents :: IO [[String]]
    let xs = map (\l -> (map (read :: String -> Int) (init l), last l)) ll
    print $ solve xs