import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		sc.close();

		Set<Integer> set = new HashSet<>();
		int r = n - 1;
		for (int i = 0; i < n; i++) {
			if (!set.add(a[i])) {
				r = i;
				break;
			}
		}

		set.clear();
		int l = 0;
		for (int i = n - 1; i >= 0; i--) {
			if (!set.add(a[i])) {
				l = i;
				break;
			}
		}

		int ans = Math.max(r - l, 0);
		System.out.println(ans);
		if (ans == 0) {
			System.out.println();
		} else {
			StringBuilder sb = new StringBuilder();
			for (int i = l; i < r; i++) {
				sb.append(i + 1).append(' ');
			}
			sb.deleteCharAt(sb.length() - 1);
			System.out.println(sb.toString());
		}
	}
}