let solve k a_arr =
    let a_arr' =
        List.filter ((<) 0) a_arr
        |> List.sort (fun a1 a2 -> a2 - a1) in
    let len_a_arr' = List.length a_arr' in
    let rec solve' idx acc =
        if idx >= len_a_arr' || idx >= k then
            acc
        else
            solve' (idx + 1) (acc + (List.nth a_arr' idx))
    in
    solve' 0 0

let () =
    let n, k =
        read_line ()
        |> fun l -> Scanf.sscanf l "%d %d" (fun n k -> (n, k))
    and a_arr =
        read_line ()
        |> String.split_on_char ' '
        |> List.map int_of_string
    in
    Printf.printf "%d\n" @@ solve k a_arr