from collections import Counter,defaultdict

def main():
    N = int(input())
    A = list(map(int, input().split()))
    
    l,r = set(),set()
    d_l,d_r = defaultdict(int),Counter(A)

    for k in d_r.keys():
        if d_r[k] > 1:
            r.add(k)
    
    ans = []

    for i,a in enumerate(A[:-1]):
        d_l[a] += 1
        if d_l[a] > 1:
            l.add(a)
        
        d_r[a] -= 1
        if d_r[a] <= 1 and a in r:
            r.remove(a)
        
        if not(l or r):
            ans.append(i+1)
    
    print(len(ans))
    print(*ans)







if __name__ == "__main__":
    main()