#include <stdio.h>   
  
#define maxim(a, b) ((a > b) ? a : b)   
#define FOR(i, a, b) for (i = a; i <= b; ++i)   
#define NMax 1024   
  
int M, N, A[NMax], B[NMax], D[NMax][NMax], sir[NMax], bst;   
  
int main(void)   
{   
    int i, j;   
       
    freopen("cmlsc.in", "r", stdin);   
    freopen("cmlsc.out", "w", stdout);   
  
    scanf("%d %d", &M, &N);   
    FOR (i, 1, M)   
        scanf("%d", &A[i]);   
    FOR (i, 1, N)   
        scanf("%d", &B[i]);   
  
for (int i=1; i<=n; i++)
	 for (int j=1; j<=m; j++)
	     if (v[i]==w[i])
		D[i][j]=D[i-1][j-1]+1;
	     else D[i][j]=maxim(D[i-1][j], D[i][j-1]);
     int jj, ii;
     for (ii=n, jj=m; ii;)
     {     if (v[ii]==w[jj])
	   {  sir[++aux]=v[ii];
	      ii--;
	      jj--;
	   }
	   else if (D[ii][jj-1]>D[ii-1][jj])
		   jj--;
		else ii--;
     }
    printf("%d\n", bst);   
    for (i = bst; i; --i)   
        printf("%d ", sir[i]);   
  
    return 0;   
}