#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
using mint = modint998244353;
const int dx[4]={0,1,0,-1};
const int dy[4]={1,0,-1,0};

int n;
int main(){
    cin >> n;
    vector<int> a(n);
    rep(i,n) cin >> a[i];
    map<int,vector<int>>mp;
    rep(i,n) mp[a[i]].push_back(i);
    int l=0;
    int r=n-1;
    for(auto p:mp){
        if(p.second.size()>2){
            cout << 0 << endl;
            cout<<" "<<endl;
            return 0;
        }
        if(p.second.size()==2){
            l=max(l,p.second[0]);
            r=min(r,p.second[1]);
        }
    }
    cout << max(0,r-l) << endl;
    for(int i=l;i<r;i++) cout << i+1 << " ";
    cout<<endl;
    return 0;
}