#include <bits/stdc++.h>
#define NMax 1030
#define pb push_back
#define po pop_back
 
using namespace std;
 
ifstream f("cmlsc.in");
ofstream g("cmlsc.out");
 
int n,m;
int A[NMax], B[NMax];
int M[NMax][NMax];
vector<int> solution;
 
/**
 * [CHECKED] Helping function for getting the max between two ints
 */
inline int maxim(int a, int b) {
    if (a > b)
        return a;
    return b;
}
 
/**
 * [CHECKED] Helping function for getting the min between two ints
 */
inline int minim(int a, int b) {
    return a+b-maxim(a,b);
}
 
/**
 * [CHECKED] Reading the input
 */
void read() {
    f>>n>>m;
    for (int i=1;i<=n;i++)
        f>>A[i];
    for (int j=1;j<=m;j++)
        f>>B[j];
}
 
/**
 * [CHECKED] Outputing the solutions vector
 */
void outputSolution() {
    g<<endl;
    int size = solution.size();
    for (int i = size-1; i >= 0; i--) {
		g<<solution[i]<<' ';
	}
}
 
/**
 * Function for finding the solution of the input with the help of DP in reverse
 */
void findSolution() {
    int i = n, j = m;
    while (i >= 1 && j >= 1) {
        if (M[i][j] == 1+M[i-1][j-1] && A[i] == B[j]) {
            solution.pb(A[i]);
            i--; j--;
        } else {
            if (M[i-1][j] > M[i][j-1])
                i--;
            else
                j--;
        }
    }
     
    outputSolution();
}
 
/**
 * [CHECKED] DP applied on the input read
 */
void solve() {
    for (int i=1;i<=n;i++) {
        for (int j=1;j<=m;j++) {
            if (A[i] == B[j])
                M[i][j] = maxim(maxim(M[i-1][j], M[i][j-1]), 1+M[i-1][j-1]);
            else
                M[i][j] = maxim(M[i-1][j], M[i][j-1]);
        }
    }
     
    g<<M[n][m];
     
    findSolution();
}
 
/**
 * [CHECKED] Starting the program
 */
int main() {
     
    read();
    solve();
     
    f.close(); g.close();
    return 0;
}