n=int(input())
L=list(map(int,input().split()))
SL,SR=set(),set()
from collections import defaultdict
dr=defaultdict(int)

for e in L:
	dr[e]+=1
	if 2<=dr[e]:
		SR.add(e)

ans=[]
for i in range(n-1):
	e=L[i]
	if e not in SL:
		SL.add(e)
	else:
		break
	dr[e]-=1
	if dr[e]<=1:
		SR-={e}
	if SR==set():
		ans.append(i+1)
print(len(ans))
print(*ans)