Scanf.scanf "%s" (fun s ->
    let d = Array.make 10 0 in
    String.iter (fun c -> let q = int_of_char c - 48 in d.(q) <- d.(q) + 1) s;
    for i = 9 downto 0 do
        print_string (String.make d.(i) "0123456789".[i])
    done;
    print_newline ()
)