from collections import*
n,*a=map(int,open(0).read().split())
r=Counter(a)
l=Counter()
sr=sum(v>1 for v in r.values())
sl=0
ans=[]
for i in range(n-1):
  l[a[i]]+=1
  if l[a[i]]==2:
    sl+=1
  r[a[i]]-=1
  if r[a[i]]==1:
    sr-=1
  if sl==sr==0:
    ans+=i+1,
print(len(ans))
print(*ans)