#include<bits/stdc++.h>
using namespace std;
using ll=long long;
#define rep(i,s,t) for(ll i=s;i<(ll)(t);i++)
#define rrep(i,s,t) for(ll i=(ll)(t)-1;i>=(ll)s;i--)
#define all(x) begin(x),end(x)
#define rall(x) rbegin(x),rend(x)

#define TT template<typename T>
TT using vec=vector<T>;
TT bool chmin(T &x,T y){return x>y?(x=y,true):false;}
TT bool chmax(T &x,T y){return x<y?(x=y,true):false;}

struct io_setup{
    io_setup(){
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
        cout<<fixed<<setprecision(15);
    }
} io_setup;

const int C[6]={720,360,180,30,6,1};
const char S[6]={'C','M','S','R','o','.'};

int main(){
    int N;
    cin>>N;
    vector<int>A(N);
    for(int i=0;i<N;i++)cin>>A[i];
    set<int>sel;
    int l=-1;
    for(int i=0;i<N;i++){
        if(sel.count(A[i])){
            l=i;
            break;
        }
        sel.insert(A[i]);
    }
    set<int>ser;
    int r=-1;
    for(int i=N-1;i>=0;i--){
        if(ser.count(A[i])){
            r=i;
            break;
        }
        ser.insert(A[i]);
    }
    vector<int>ans;
    if(l==-1){
        for(int i=0;i<N-1;i++)ans.push_back(i+1);
    }else{
        for(int i=r;i<=l-1;i++)ans.push_back(i+1);
    }
    int L=ans.size();
    cout<<L<<"\n";
    for(int i=0;i<L;i++){
        cout<<ans[i];
        if(i<L-1)cout<<" ";
    }
    cout<<"\n";
}