import java.io.*; import java.util.*; import java.util.function.*; import java.util.stream.*; public class Main { public static void main(String[] args) throws Exception { Scanner sc = new Scanner(); int n = sc.nextInt(); int[] values = new int[n]; for (int i = 0; i < n; i++) { values[i] = sc.nextInt(); } Set leftExist = new HashSet<>(); int left = 0; for (int i = 0; i < n && !leftExist.contains(values[i]); i++) { left = i; leftExist.add(values[i]); } Set rightExist = new HashSet<>(); int right = 0; for (int i = n - 1; i >= 0 && !rightExist.contains(values[i]); i--) { right = i; rightExist.add(values[i]); } List ans = new ArrayList<>(); for (int i = Math.max(1, right); i <= left + 1 && i < n; i++) { ans.add(i); } System.out.println(ans.size()); System.out.println(ans.stream().map(x -> x.toString()).collect(Collectors.joining(" "))); } } class Scanner { BufferedReader br; StringTokenizer st = new StringTokenizer(""); StringBuilder sb = new StringBuilder(); public Scanner() { try { br = new BufferedReader(new InputStreamReader(System.in)); } catch (Exception e) { } } public int nextInt() { return Integer.parseInt(next()); } public long nextLong() { return Long.parseLong(next()); } public double nextDouble() { return Double.parseDouble(next()); } public String next() { try { while (!st.hasMoreTokens()) { st = new StringTokenizer(br.readLine()); } } catch (Exception e) { e.printStackTrace(); } finally { return st.nextToken(); } } }