let () =
  let rec read () =
    let k = read_int () in
    if k = 0 then ()
    else
      begin
        let c = read_line ()
                |> Str.split (Str.regexp " ")
                |> List.fold_left (fun x y -> x + (int_of_string y) ) 0
        in
        Printf.printf "%d\n" (c/(k-1));
        read ()
      end
  in read ()
;;