#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int n;
  cin >> n;
  vector<int> a(n);
  rep(i, n) cin >> a[i];
  map<int, int> left, right;
  rep(i, n) right[a[i]]++;
  int left_cnt = 0, right_cnt = 0;
  for (auto [k, v] : right) {
    if (v > 1) right_cnt++;
  }
  vector<int> ans(0);
  rep(i, n - 1) {
    int x = a[i];
    right[x]--;
    if (right[x] == 1) right_cnt--;
    if (right[x] == 0) right.erase(x);
    left[x]++;
    if (left[x] == 2) left_cnt++;
    if (left_cnt == 0 && right_cnt == 0) ans.push_back(i + 1);
  }
  cout << ans.size() << endl;
  for (int x : ans) cout << x << ' ';
  cout << endl;
  return 0;
}