let () = Scanf.scanf "%d %d %s" @@ fun a b s ->
  Array.init (a + b + 1) (fun i ->
    if i = a then s.[i] = '-' else s.[i] <> '-')
  |> Array.fold_left ( && ) true
  |> (function true -> "Yes" | false -> "No")
  |> print_endline