main :: IO ()
main = do
  s <- getLine
  putStrLn $ if easilyPlyable s then "Yes" else "No"

easilyPlyable :: String -> Bool
easilyPlyable []        = True
easilyPlyable ('L':_)   = False
easilyPlyable [_]       = True
easilyPlyable (_:'R':_) = False
easilyPlyable (_:_:xs)  = easilyPlyable xs