import Control.Arrow
import Control.Monad
import Data.List
import qualified Data.ByteString.Char8 as B

main :: IO ()
main = readLine >>= printRes . solve 
    where
        printRes b
            | b = putStrLn "Yes"
            | otherwise = putStrLn "No"

solve :: [Int] -> Bool
solve = (== 1) . length . group . sort

readLine :: IO [Int]
readLine = unfoldr (fmap (second (maybe B.empty snd . B.uncons)) . B.readInt) <$> B.getLine

readContents :: Int -> IO [[Int]]
readContents = flip replicateM readLine