let split_on_char sep s =
  let r = ref [] in
  let j = ref (String.length s) in
  for i = String.length s - 1 downto 0 do
    if String.unsafe_get s i = sep then begin
      r := String.sub s (i + 1) (!j - i - 1) :: !r;
      j := i
    end
  done;
  String.sub s 0 !j :: !r;;

let rec fruit_left result n lst =
  match n with
  | 0 -> result
  | _ ->
    let next = List.hd lst in
    if (next < 1) then result else fruit_left (result + next) (n - 1) (List.tl lst);;

let () =
  let raw = read_line () |> split_on_char ' ' |> List.map int_of_string in
  let k = List.nth raw 1 in
  let fruit = read_line () |> split_on_char ' ' |> List.map int_of_string
              |> List.fast_sort (fun x y -> - (compare x y )) in
  let first = List.hd fruit in
  let fruit = List.tl fruit in
  fruit_left first (k - 1) fruit |> print_int; print_newline ();;