#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#ifdef LOCAL
#include <algo/debug.h>
#else
#define debug(...) void(0)
#endif

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    ll N; cin >> N;
    vector<ll> A(N); for(int i = 0; i < N; i++) cin >> A[i];
    map<ll, ll> MP1, MP2; for(int i = 0; i < N; i++) MP2[A[i]]++;
    set<ll> S1, S2;
    for(auto&&[a, b]: MP2) {
        if(b >= 2) {
            S2.emplace(a);
        }
    }
    vector<int> ans;
    for(int i = 0; i < N - 1; i++) {
        MP2[A[i]]--; MP1[A[i]]++;
        if(MP2[A[i]] <= 1) S2.erase(A[i]);
        if(MP1[A[i]] >= 2) S1.emplace(A[i]);
        if(S1.empty() && S2.empty()) {
            ans.push_back(i + 1);
        }
    }
    cout << int(ans.size()) << endl;
    for(auto&&a : ans) {
        cout << a << " ";
    }cout << endl;
}