let () =
  let n, a = Scanf.scanf "%d %d\n" (fun n a -> n, a) in
  let lst = Array.to_list (Array.init n (fun _ -> Scanf.scanf "%d " (fun x -> x))) in
  let s = float_of_int (List.fold_left (+) 0 lst) /. float_of_int n in
  Printf.printf "%s\n" (if float_of_int a = s then "YES" else "NO")