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 = (List.fold_left (+) 0 lst) / n in
    Printf.printf "%s\n" (if a = s then "YES" else "NO")