let () =
  let n, a = Scanf.scanf "%d %d " (fun n a -> n, a) in
  let x = Array.init n (fun _ -> Scanf.scanf "%d " (fun i -> i)) in
  let m = float (Array.fold_left (+) 0 x) /. float n in
  print_endline (if float a = m then "YES" else "NO")