N = int(input())
A = list(map(int, input().split()))
# 全部異なる文字のとき
if len(set(A))==N:
	print(N-1)
	print(" ".join(map(str,range(1,N))))
	exit()
# 左側に重複要素が存在しないiの最小値をもとめる
ng = -1
ok = N
while True:
	left = (ok + ng)//2
	if len(set(A[:left]))!=left:
		ok = left
	else:
		ng = left
	if ng==ok-1:
		break
left = ng
# 右側に重複要素が存在しないiの最大値をもとめる
ng = -1
ok = N
while True:
	right = (ok + ng)//2
	if len(set(A[right:]))!=N-right:
		ng = right
	else:
		ok = right
	if ng==ok-1:
		break
right = ok
ans = range(right, left+1)
print(len(ans))
print(" ".join(map(str,ans)))
"🐬"