from collections import Counter

n = int(input())

arr = list(map(int, input().split()))

l = Counter()
r = Counter(arr)
ll = Counter()
rr = Counter()
for c in r:
    rr[r[c]] += 1
res = []

for i in range(n - 1):
    if l[arr[i]] > 0:
        ll[l[arr[i]]] -= 1
    l[arr[i]] += 1
    ll[l[arr[i]]] += 1
    rr[r[arr[i]]] -= 1
    r[arr[i]] -= 1
    if r[arr[i]] > 0:
        rr[r[arr[i]]] += 1
    if ll[1] == i + 1 and rr[1] == n - i - 1:
        res.append(i + 1)
       
print(len(res))
print(*res)