from collections import defaultdict
n = int(input())
a = list(map(int, input().split()))
s1, s2 = set([a[0]]), set(a[1:])
t1, t2 = defaultdict(int), defaultdict(int)
t1[a[0]] += 1
for i in range(1, n): t2[a[i]] += 1
ans = []
for i in range(1, n):
    if len(s1) == i and len(s2) == (n-i): ans.append(i)
    if i == n-1: break
    t2[a[i]] -= 1
    t1[a[i]] += 1
    if t2[a[i]] <= 0: s2.remove(a[i])
    s1.add(a[i])
print(len(ans))
print(*ans)