let dig_of_char (c:char) = int c - int '0'
let char_of_dig (d:int) = char (d + int '0')

let solve s =
  let sarr = Array.create  10 0 in
  let slen = String.length s in

  let rec make_arr idx =
    if idx < slen then (
      let dig = dig_of_char s.[idx] in
      sarr.[dig] <- sarr.[dig] + 1;
      make_arr (idx + 1)
    )
  in
  make_arr 0;
  seq {9..-1..0} |>
  Seq.map (fun i -> new System.String(char_of_dig i, sarr.[i])) |>
  Seq.fold ( + ) ""

let () =
  let n = stdin.ReadLine() in
  solve n |> printfn "%s"