#include <fstream> 
#include <iostream> 

using namespace std; 

#define FIN "cmlsc.in" 
#define FOUT "cmlsc.out" 
#define N_MAX 1025 

ifstream fin(FIN); 
ofstream fout(FOUT); 

int n,m; 
short c[N_MAX][N_MAX],b[N_MAX][N_MAX]; 
short X[N_MAX],Y[N_MAX]; 

void print_lcs(int i,int j)      
{   
	if(i==0 || j==0)       
	return;   
	if(i > 0 && j >0)        
	if( b[i][j] == 1 ){            
	   print_lcs(i-1,j-1);             
	   fout << X[i] << " ";        
	} else if( b[i][j] == 2 ){            
	    print_lcs(i-1,j);          
	} else print_lcs(i,j-1); 
} 

int lcs_length() 
{     
int i,j;      

for(i = 0; i < n; ++i) c[i][0] = 0; 
for(j = 1; j <= m; ++j) c[0][j] = 0; 
for(i = 1; i <= n; ++i) 
 for(j = 1; j <= m; ++j) 
         if( X[i] == Y[j] ) { 
           c[i][j] = c[i-1][j-1] +1,b[i][j] = 1;          
} else if (c[i-1][j]  > c[i][j-1]) 
           c[i][j] = c[i-1][j], b[i][j] = 2;              
  else       c[i][j] = c[i][j-1], b[i][j] = 3;     
  fout << c[n][m] << endl; 
  print_lcs(n,m);
} 
 

void read_data() 
{     
	fin >> n >> m;     
	for(int i = 1; i <= n; ++i) fin >> X[i];  
	for(int i = 1; i <= m; ++i) fin >> Y[i];      
}  


int main() 
{ 
    	read_data(); 
    	lcs_length();      
	fout << endl;
return 0; 
}