/*
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,fma,bmi,bmi2,sse4.2,popcnt,lzcnt")
*/

#include <bits/stdc++.h>
#define taskname ""
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define i64 long long
#define pb push_back
#define ff first
#define ss second
#define isz(x) (int)x.size()
using namespace std;

const int mxN = 2e5 + 5;
const int mod = 1e9 + 7;
const i64 oo = 1e18;

void solve() {
    int n;
    cin >> n;

    vector<int> a(n);
    for (auto &val : a) cin >> val;

    int r = n - 1, l = 0;
    map<int, int> mp;
    for (int i = 0; i < n; ++i) {
        if (++mp[a[i]] == 2) {
            r = i;
            break;
        }
    }

    mp.clear();
    for (int i = n - 1; i >= 0; --i) {
        if (++mp[a[i]] == 2) {
            l = i;
            break;
        }
    }

    cout << max(0, r - l) << endl;
    for (int i = l; i < r; ++i) cout << i + 1 << " ";
    cout << endl;
}

signed main() {

#ifndef CDuongg
    if(fopen(taskname".inp", "r"))
        assert(freopen(taskname".inp", "r", stdin)), assert(freopen(taskname".out", "w", stdout));
#else
    freopen("bai3.inp", "r", stdin);
    freopen("bai3.out", "w", stdout);
    auto start = chrono::high_resolution_clock::now();
#endif

    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1; //cin >> t;
    while(t--) solve();

#ifdef CDuongg
   auto end = chrono::high_resolution_clock::now();
   cout << "\n"; for(int i = 1; i <= 100; ++i) cout << '=';
   cout << "\nExecution time: " << chrono::duration_cast<chrono::milliseconds> (end - start).count() << "[ms]" << endl;
   cout << "Check array size pls sir" << endl;
#endif

}