#include <fstream>
#include <algorithm>

using namespace std;

int n,nr,m,a[1024],b[1024],c[1024],d[1024][1024];

ifstream cin("cmlsc.in");
ofstream cout("cmlsc.out");

int main()
{
    int i,j;
    for(i=1;i<=n;++i)
       cin>>a[i];
    for(i=1;i<=m;++i)
       cin>>b[i];
    for(i=1;i<=n;++i)
       for(j=1;j<=m;++j)
          if(a[i]==b[j])
            d[i][j]=d[i-1][j-1]+1;
            else d[i][j]=max(d[i-1][j],d[i][j-1]);
    cout<<d[n][m]<<"\n";
    i=n; j=m;
    while(i!=0 &&j!=0)
    {
        if(a[i]==b[j])
        {
            nr++;
            c[nr]=a[i];
            i--; j--;
        }
        else
            if(d[i-1][j]>d[i][j-1])
               i--;
             else
               j--;
    }
    for(i=nr;i>=1;i--)
        cout<<c[i]<<" ";

    return 0;
}