#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
int N;
vector<int> A;

void solve(){
    int lcnt = 0,rcnt = 0;
    map<int,int> l,r;
    for(int i = 0;i<N;i++){
        r[A[i]]++;
        if(r[A[i]] == 2){
            rcnt++;
        }
    }
    vector<int> ans;
    for(int i = 0;i<N-1;i++){
        l[A[i]]++;
        r[A[i]]--;
        if(l[A[i]] == 2){
            lcnt++;
        }
        if(r[A[i]] == 1){
            rcnt--;
        }
        if(lcnt ==0 && 0 == rcnt){
            ans.push_back(i+1);
        }
    }
    cout<<ans.size()<<endl;
    for(int i = 0;i<ans.size();i++){
        cout<<ans[i]<<' ';
    }
    cout<<endl;
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> N;
    A.resize(N);
    for(int i = 0; i < N; i++){
        cin >> A[i];
    }
    solve();
}