import os, sys
import math, decimal, queue, heapq, bisect, itertools, functools, collections, string
from bisect import bisect, bisect_left
from collections import defaultdict, OrderedDict, deque, Counter
from functools import cmp_to_key, lru_cache, reduce
from heapq import heapify, heappush, heappushpop, heappop, heapreplace, nlargest, nsmallest
from itertools import accumulate, chain, combinations, combinations_with_replacement, compress, count, cycle, dropwhile, filterfalse, groupby, islice, permutations, product, repeat, starmap, takewhile, tee, zip_longest
from math import gcd, factorial, isqrt, comb, perm, prod, inf
from queue import Queue, PriorityQueue, LifoQueue
from string import ascii_letters, ascii_lowercase, ascii_uppercase, digits, hexdigits, octdigits

LOCAL = sys.argv[0] if '4a' in sys.argv[0] else None

P = lambda *p: [print(i, end='	') for i in p] if LOCAL else None
PI = lambda *p: print(' '.join(map(str, p))) or None
PII = lambda X: [PI(*row) for row in X]

sys.stdin = open(os.path.join(os.getcwd(), 'a1.txt'), 'r') if LOCAL else sys.stdin
I = lambda: [int(a) for l in sys.stdin for a in l.strip().split()]
S = lambda: [a for l in sys.stdin for a in l.strip().split()]
IM = lambda: [[int(a) for a in l.split()] for l in sys.stdin]
SM = lambda: [[a for a in l.split()] for l in sys.stdin]

az, AZ, mod = ascii_lowercase, ascii_uppercase, 1_000_000_007

A = IM()
# P(A)


def solution(A):
    N = A[0][0]
    B = A[1]
    # P(N, B)
    l, r = set(), set()
    out = 0
    res = []
    c = Counter()
    d = Counter(B)
    for i, num in enumerate(B):
        # P(c, d, '\n')
        c[num] += 1
        d[num] -= 1
        x = c.most_common()[0][1]
        y = d.most_common()[0][1]
        # P(x, y, c, d, '\n')
        if x <= 1 and y <= 1:
            out += 1
            res += [i + 1]
    print(out)
    PI(*res)


solution(A)