from collections import defaultdict
n=int(input())
A=list(map(int,input().split()))
D=defaultdict(list)
for i,j in enumerate(A):
    D[j].append(i+1)
l,r=1,n-1
for I in D.values():
    if len(I)>2:
        print(0)
        exit()
    elif len(I)==2:
        l=max(l,min(I))
        r=min(r,max(I)-1)
if r-l+1<=0:
    print(0)
    exit()
print(r-l+1)
print(*[i for i in range(l,r+1)])