#include <bits/stdc++.h>
using namespace std;

ifstream fin("frunze.in");
ofstream fout("frunze.out");

vector <int> a[105];
int sol[105];
int n,k,mak;

int main()
{
    int i,x,r=1;
    fin >> n;
    for(i=1;i<=n;i++){
        fin >> x;
        if(x==0) r=i;
        else a[x].push_back(i);
    }
    fout << r << "\n";
    for(i=1;i<=n;i++) if(a[i].size()==0) sol[++k]=i;
    fout << k << "\n";
    for(i=1;i<=k;i++) fout << sol[i] << " ";
    return 0;
}