from collections import Counter


def main():
    N = int(input())
    A = list(map(int, input().split()))

    left_ctr = Counter()
    right_ctr = Counter(A)
    left_dup_flag = False
    right_dup_nums = set()
    for n, v in right_ctr.items():
        if v > 1:
            right_dup_nums.add(n)

    ans = []
    for idx in range(N - 1):
        move_n = A[idx]
        right_ctr[move_n] -= 1
        if right_ctr[move_n] == 1:
            right_dup_nums.remove(move_n)
        if left_ctr[move_n] > 0:
            left_dup_flag = True
        left_ctr[move_n] += 1
        if not left_dup_flag and not right_dup_nums:
            ans.append(idx)
    print(len(ans))
    print(*map(lambda n: n + 1, ans))


if __name__ == "__main__":
    main()