#include<stdio.h>
FILE *f,*g;   
int a[1025],b[1025],c[1025],d[1025],o,n,m,i,j,max,nr,t;   
int main()   
{   
f=fopen ("cmlsc.in","rt");   
g=fopen ("cmlsc.out","wt");   
fscanf(f,"%d %d\n",&n,&m);   
for (i=1;i<=n;i++)   
    fscanf(f,"%d",&a[i]);   
for (i=1;i<=m;i++)   
    fscanf(f,"%d",&b[i]);   
o=1;   
for (i=1;i<=m;i++)   
    {   
    t=o;   
    nr=1;   
    for (j=t;j<=n;j++)   
        if (b[i]==a[j]) {c[nr++]=b[i];o=t+1;i++;}
        else if (j==n&&i<m) {j=t;i++;}
    if (nr>max) {max=nr;d[0]=nr;for(j=1;j<=nr;j++)d[j]=c[j]; }   
    for (j=1;j<=nr;j++)   
        c[j]=0;
    }
d[0]--;
fprintf(g,"%d\n",d[0]);
for (j=1;j<=d[0];j++)   
    fprintf(g,"%d ",d[j]);   
fprintf(g,"\n");   
fclose(f);   
fclose(g);   
return 0;   
}