#include <iostream>

#include<fstream>

#include<string>

using namespace std;

ifstream in("cmlsc.in");

ofstream out("cmlsc.out");

int*first;

int l1;

int*second;

int l2;

void lcs(int*first,int*last,int l1,int l2)

{

    int freq[l1+1][l2+1];

    for(int i=0; i<=l1; i++)

    {

        for(int k=0; k<=l2; k++)

        {

            if(!i||!k)

            {

                freq[i][k]=0;

            }

            else if(first[i-1]==last[k-1])

            {

                freq[i][k]=freq[i-1][k-1]+1;

            }

            else

            {

                freq[i][k]=max(freq[i-1][k],freq[i][k-1]);

            }

        }

    }

    int x=l1,y=l2;

    int a[10000];

    int p=0;

    out<<freq[x][y]<<endl;

    while(x&&y)

    {

        if(first[x-1]==second[y-1])

        {

            a[p]=first[x-1];

            p++;

            x--;

            y--;

        }

        else

        {

            if(freq[x-1][y]>=freq[x][y-1])

            {

                x--;

            }

            else

                y--;

        }

        //cout<<x<<" "<<y<<endl;

    }

    for(int i=p-1; i>=0; i--)

        out<<a[i]<<" ";



}

void citire()

{

    in>>l1>>l2;

    first=new int[l1];

    second=new int[l2];

    int i;

    for(i=0; i<l1; i++)

        in>>first[i];

    for(i=0; i<l2; i++)

        in>>second[i];

}

int main()

{

    citire();

    lcs(first,second,l1,l2);

}