#include <stdio.h>
 
#define NMax 260
 
int M, N, a[NMax], b[NMax];
 

void back(int m, int n)
{
	int i;
    int **mat = calloc(n, sizeof(int*));
	for(i = 0; i < n; i++)
		mat[i] = calloc(m, sizeof(int));
	
	int j;
	for(int i = 1; i < n; i++)
		for(int j = 1; j < m; j++){
			if(a[j-1] == b[i-1])
				mat[i][j] = mat[i-1][j-1] + 1;
			else 
				mat[i][j] = (mat[i][j-1] > mat[i-1][j] ? mat[i][j-1] : mat[i-1][j]);
		}
		
	printf("%d\n", mat[n-1][m-1]);
	i = n;
	j = m;
	int k[NMax];
	int l=0;
	while(mat[i][j] != 0){
		if (mat[i-1][j-1] == mat[i][j] - 1){
			k[l++] = a[j-1];
			i--;j--;
		} else if(mat[i][j] == mat[i-1][j])
			i--;
		else
			j--;
	}
	
	for(i = 0; i < l; i++)
		(i < l - 1 ? printf("%d ", k[i]) : printf("%d", k[i]);
}
 
int main(void)
{
    int i;
     
    freopen("cmlsc.in", "r", stdin);
    freopen("cmlsc.out", "w", stdout);
 
    scanf("%d %d", &M, &N);
    for (i = 1; i <= M; i++)
        scanf("%d", &a[i]);
    for (i = 1; i <= N; i++)
        scanf("%d", &b[i]);
 
	back(M+1, N+1);
	
    return 0;
}