import collections,sys,math,functools,operator,itertools,bisect,heapq,decimal,string,time,random
#sys.setrecursionlimit(10**9)
#sys.set_int_max_str_digits(0)
#input = sys.stdin.readline

#
#alist = []

n = int(input())
a = list(map(int,input().split()))
x = [0 for i in range(n)]
s = set()
for i in range(n):
    if a[i] in s:
        break
    s.add(a[i])
    x[i] = 1
y = [0 for i in range(n)]
s = set()
for i in reversed(range(n)):
    if a[i] in s:
        break
    s.add(a[i])
    y[i] = 1
ans = []
for i in range(n-1):
    if x[i] and y[i+1]:
        ans.append(i+1)
print(len(ans))
print(*ans)