#include <fstream>
#define maxim(a,b) ((a>b)? a : b)
#define For(i, a, b) for (i = a; i <= b; ++i)
#define NMax 1024
using namespace std;
int M, N, A[NMax], B[NMax], D[NMax][NMax], sir[NMax], bst;
int main() 
{int i, j;  
ifstream f("cmlsc.in"); 
ofstream g("cmlsc.out");  
f>>M>>N; 
For(i, 1, M)    
f>>A[i];
For(i, 1, N)  
f>>B[i]; 
For(i, 1, M)
For(j, 1, N)
if (A[i] == B[j])
D[i][j] = 1 + D[i-1][j-1];
else
D[i][j] = maxim(D[i-1][j], D[i][j-1]);
for(i=M, j=N; i;)
if(A[i] == B[j])
sir[++bst] = A[i], --i, --j;
else if (D[i-1][j] < D[i][j-1])
--j;
else --i;  
g<<bst<<"\n";
for(i=bst; i; --i) 
g<<sir[i]<<' '; 
f.close(); g.close();}