#include <iostream>
#include <fstream>

using namespace std;

int main() {

  ifstream fin("input.txt");
  ofstream fout("output.txt");

  int a[5];
  int b[5];
  int c[10];

  int na, nb;
  fin >> na;
  for (int i = 0; i < na; i++)
    fin >> a[i];
  fin >> nb;
  for (int i = 0; i < nb; i++)
    fin >> b[i];
  int count = 0;

  for (int i = 0; i < na; i++)
    for (int j = 0; j < nb; j++)
      if (a[i] == b[j]) {
        c[count] = a[i];
        count++;
        b[j] = -100000000;
      }

  fout << count << '\n';
  for (int i = 0; i < count; i++)
    fout << c[i] << ' ';
  fout << '\n';

  return 0;
}