let solve a s =
  let len = String.length s in
  let rec aux i =
    if i >= len then "Yes"
    else if i = a && s.[i] <> '-' then "No"
    else if s.[i] <> '-' then aux (i + 1)
    else "No"
  in
  aux 0


let () = Scanf.scanf "%d %d\n%s" (fun a _ s -> solve a s) |> print_endline
