N = int(input())
A = [0]+list(map(int,input().split()))
j = 1
flagL = 0
flagR = 0
L = {}
L[A[1]] = 1
R = {}
for i in range(N,j,-1):
    R[A[i]] = R.get(A[i],0)+1
    if R[A[i]]==2:
        flagR += 1
ans = []
if flagL==0 and flagR==0:
    ans.append(1)
for j in range(2,N):
    a = A[j]
    L[a] = L.get(a,0)+1
    if L[a]==2:
        flagL += 1
    R[a] -= 1
    if R[a]==1:
        flagR -= 1
    if flagL==0 and flagR==0:
        ans.append(j)
print(len(ans))
print(*ans)