let () = Scanf.scanf "%s" @@ fun s ->
  let n = String.length s in
  let easy = ref true in
  for i = 0 to n - 1 do
    if i mod 2 = 0 && s.[i] = 'L' then easy := false
    else if i mod 2 = 1 && s.[i] = 'R' then easy := false
  done;
  Printf.printf "%s\n" @@
  if !easy then "Yes" else "No"