import qualified Data.ByteString.Char8 as B

data YesNo = Yes | No deriving Show


solve :: B.ByteString -> YesNo
solve s = if u == B.reverse u && v == B.reverse v && s == B.reverse s then Yes else No
    where n = B.length s
          u = B.take ((n - 1) `div` 2) s
          v = B.drop ((n + 1) `div` 2) s

main :: IO ()
main = B.getLine >>= print . solve