judge [] = True
judge (x:xs) = (x == 'R' || x == 'U' || x == 'D') && judge' xs

judge' [] = True
judge' (x:xs) = (x == 'L' || x == 'U' || x == 'D') && judge xs

main = do
	s <- getLine
	putStrLn $ if judge s then "Yes" else "No"
