//分发礼物 public class IDreward { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); LinkedHashSet<Integer> set = new LinkedHashSet<>(); for (int i = 0; i < n; i++) { set.add(sc.nextInt()); } List<Integer> list = new LinkedList<>(set); int m = Math.min(10, list.size()); System.out.println(m); for (int i = 0; i < m; i++) { System.out.println(list.get(i)); } } }