#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
using mint = atcoder::modint1000000007;
const ll inf = 9e18;

int main(){

	ios::sync_with_stdio(0);
	cin.tie(0);

    ll n;
    cin >> n;

    vector<ll> a(n);
    map<ll,ll> g1,g2;
    map<ll,bool> is_separated;
    ll cnt=0;

    for(ll i=0;i<n;i++){
        cin >> a[i];
        g2[a[i]]++;
        g1[a[i]]=0;
        if(g2[a[i]]==1){
            is_separated[a[i]]=true;
            cnt++;
        }
        if(g2[a[i]]>1){
            is_separated[a[i]]=false;
            cnt--;
        }
    }

    vector<ll> ans;

    for(ll i=0;i<n-1;i++){
        g1[a[i]]++;
        g2[a[i]]--;
        if(is_separated[a[i]]==false&&g1[a[i]]<=1&&g2[a[i]]<=1){
            cnt++;
            is_separated[a[i]]=true;
        }
        if(is_separated[a[i]]==true&&(g1[a[i]]>=2||g2[a[i]]>=2)){
            cnt--;
            is_separated[a[i]]=false;
        }
        if(cnt==is_separated.size()) ans.push_back(i+1);
    }

    cout << ans.size() << endl;
    for(ll idx:ans) cout << idx << " ";
    
}