#include <fstream>
using namespace std;
ifstream fin("cmlsc.in");
ofstream fout("cmlsc.out");
int n,m,sol[100][100],a[100],b[100],vec[100],k=1;
int main()
{
    fin>>n>>m;
    sol[0][0]=0;
    for(int i=1; i<=n; i++){
        fin>>a[i];
        sol[0][i]=0;}
    for(int i=1; i<=m; i++){
        fin>>b[i];
        sol[i][0]=0;}

    for(int i=1; i<=n; i++)
    for(int j=1; j<=m; j++){
        if(a[i]==b[j]){
            vec[k++]=a[i];
            sol[i][j]=sol[i-1][j-1]+1;
        }
        else{
            if(sol[i-1][j]>sol[i][j-1])
                sol[i][j]=sol[i-1][j];
            else
                sol[i][j]=sol[i][j-1];
        }
    }

    fout<<sol[n][m]<<'\n';
    for(int i=1; i<=sol[n][m]; i++)
        fout<<vec[i]<<" ";

    return 0;
}