#include <fstream>

using namespace std;

fstream f;
fstream g;
int m,n;
int a[1024];
int b[1024];
int i,j;
int vect[1024];
char l1[1024];
int lungime;
int x;
int vect2[1024];
int lungime2;

int main()
{
    f.open("cmlsc.in",fstream::in);
    f >> m >> n;
    for(i=0;i<m;i++)
       f >> a[i]; 
    for(i=0;i<n;i++)
      f>> b[i];       
    f.close();
    
    
    g.open("cmlsc.out",fstream::out);
 
    for(i=0;i<m;i++)
             for(j=x;j<n;j++)
                if(a[i]==b[j]&&!l1[j])
                   {
                       vect[lungime++]=a[i];
                       l1[j]=1;
                       x=j;
                       break;                   
                   }
    x=0;
    
         for(i=0;i<n;i++)
             for(j=x;j<m;j++)
                if(b[i]==a[j]&&!l1[j])
                   {
                       vect2[lungime2++]=b[i];
                       l1[j]=1;
                       x=j;
                       break;                   
                   }
    
    if(lungime>lungime2)
    {
       g << lungime  << "\n";
       for(i=0;i<lungime;i++)
          g << vect[i] << " ";
     }
      else
      {
           g << lungime2 << "\n";
           for(i=0;i<lungime2;i++)
             g << vect2[i] << " ";
             }
    g.close();    
    return 0;
    
}