from collections import defaultdict
N = int(input())
A = input().split()
D = defaultdict(list)
lower = 1
upper = N
for i in range(N):
    D[A[i]].append(i+1)
    if len(D[A[i]]) > 2:
        print(0)
        print()
        exit()
    elif len(D[A[i]]) == 2:
        lower = max(lower, D[A[i]][0])
        upper = min(upper, D[A[i]][1])
print(max(upper-lower, 0))
print(*range(lower, upper))