-- Try AtCoder
-- author: Leonardone @ NEETSDKASU

import Data.Map as Map

main = putStrLn . solve  =<< getLine


solve s = if ans then "Yes" else "No" where
    f []     m = m
    f (x:xs) m = f xs h where
        h = case Map.lookup x m of
            Just c -> Map.insert x (c + 1) m
            Nothing -> Map.insert x 1 m
    ans = all even . Map.elems $ f s Map.empty