import Data.Set as S
import Control.Monad

main :: IO ()
main = do
    n <- read <$> getLine
    alist <- replicateM n getLine
    putStrLn $ solve n alist

solve :: Int -> [String] -> String
solve n alist = if n > 2 && length set >= 3 then "Yes" else "No" where set = S.fromList alist