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

from collections import defaultdict
from collections import Counter
C = Counter(A)
if C.most_common()[0][1] > 2:
    # print('aaaaaa')
    print(0)
    print()
    exit()
elif C.most_common()[0][1] == 1:
    print(len(A)-1)
    print(*list(range(1, N)))
    exit()

LR = []
cnt = defaultdict(int)
stt = []
end = []
for i in range(N):
    x = A[i]
    cnt[x] += 1
    if C[x] >= 2 and cnt[x] == 1:
        stt.append(i)
    if C[x] >= 2 and cnt[x] == C[x]:
        end.append(i)
stt.sort()
end.sort()
l = stt[-1]
r = end[0]
# print(l, r, stt, end)
if l > r:
    # print(l, r, stt, end)
    print(0)
    print()
    exit()
else:
    print(r - l)
    ans = list(range(l+1, r+1))
    print(*ans)