N = int(input())
A = list(map(int, input().split()))
left = [0]
s = set([])
flag = False
for i in range(N):
    if A[i] in s:
        flag = True
    
    s.add(A[i])
    if flag:
        left.append(1)
    else:
        left.append(0)
        

right = [0]
s = set([])
flag = False
for i in reversed(range(N)):
    if A[i] in s:
        flag = True
    
    s.add(A[i])
    if flag:
        right.append(1)
    else:
        right.append(0)
right = right[::-1]
#print(left)
#print(right)
ans = []
for i in range(1,N):
    if left[i] == 0 and right[i] == 0:
        ans.append(i)
print(len(ans))
print(*ans)