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

short *a;
short *b;
vector<short>c;
short m1, m2, i,j;

int main()
{
	ifstream in("cmlsc.in");
	ofstream out("cmlsc.out");

	in >> m1;
	in >> m2;

	a = new short[m1];
	b = new short[m2];
	short index = -1;

	for (i = 0; i < m1; i++)
		in >> a[i];
	for (i = 0; i < m2; i++)
	{
		in >> b[i];
	}

	for (i=0;i<m1;i++)
		for (j = index+1; j < m2; j++)
		{
			if (a[i] == b[j])
			{
				c.push_back(a[i]);
				index = j;
			}
		}
	out << c.size() << "\n";
	for (i = 0; i < c.size(); i++)
		out << c[i] << " ";
	return 0;
}