#include <iostream>
#include <fstream>
using namespace std;

ifstream f("cmlsc.in");
ofstream g("cmlsc.out");

int main()
{
    long long M,N,i,a[1024],b[1024],c[1024];
    long long index=-1,nr=0;
    f >> M>>N;
    for (i = 0;i < M;i++)
        f >> a[i];
    for (i = 0;i < N;i++)
        f >> b[i];
    for (i = 0;i < M;i++)
    {
        int val = 0;
        int j = index + 1;
        while (j < N && val == 0)
        {
            if (a[i] == b[j])
                val = 1;
            else
                j++;
        }
        if (val == 1)
        {
            c[nr] = a[i];
            index = j;
            nr++;
        }
    }
    g << nr << endl;
    for (i = 0;i < nr;i++)
        g << c[i] << " ";
}