import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;

/**
 * <b> Algorithm on Codeforces. Problem C div 2 </b> </br>
 * @author Huynh Quang Thao
 *
 */
public class Main {

    public static void main(String[] args) throws Exception {
        Main main = new Main();
        main.run();
    }

    public void run() throws Exception {
         Scanner sc = null;
         PrintWriter pr = null;

         pr=new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
         sc = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
       //  sc = new Scanner(new File("input.txt"));

         int n = sc.nextInt();

         int[] revpath = new int[n+1];
         int[] type = new int[n+1];
         int[] count = new int[n+1];
         int[] path = new int[n+1];

         for (int i = 1; i <= n; i++) type[i] = sc.nextInt();
         for (int i = 1; i <= n; i++) {
            int a = sc.nextInt();
            // exist path from a to i
            path[a] = i;
            count[a]++;
         }

         // building rev-path
         for (int i = 1; i <= n; i++) {
             int to = path[i];
             if (count[i] == 1) revpath[to] = i;
         }

        /* for (int i = 1; i <= n; i++) {
             System.out.println(path[i]);
         }
         System.out.println("---------");

         for (int i = 1; i <= n; i++) {
             System.out.println(revpath[i]);
         }*/


         // dfs from hotel
         List<Integer> resList = new ArrayList<Integer>();
         for (int i = 1; i <= n; i++) {
             if (type[i] == 1) {
                 int v = i;
                 // dfs from v - vertex
                 List<Integer> list = new ArrayList<Integer>();
                 list.add(v);
                 while (revpath[v] != 0) {
                     v = revpath[v];
                     list.add(v);
                 }
                 if (list.size() > resList.size()) resList = list;
             }
         }

         System.out.printf("%d\n", resList.size());
         for (int i = resList.size()-1; i >= 0; i--) System.out.printf("%d ", resList.get(i));

         pr.close();
         sc.close();
    }

    public void dfs(int v) {

    }


    static class Team {
        int baloon;
        int rA;
        int rB;
        public Team(int baloon, int rA, int rB) {
            this.baloon = baloon;
            this.rA = rA;
            this.rB = rB;
        }
    }

    static class InputReader {
        public BufferedReader reader;

        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream));
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
                catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public float nextFloat() {
            return Float.parseFloat(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public BigInteger nextBigInteger() {
            return new BigInteger(next());
        }

    }
}