#include <stdio.h>
#include <stdlib.h>

int maxx(int a, int b)
{
    return a>=b?a:b;
}

int lcs( int *X, int *Y, int m, int n )
{
    if (m == 0 || n == 0)
        return 0;
    if (X[m-1] == Y[n-1]) //m-1 is the index of last element of X and same for Y
        return 1 + lcs(X, Y, m-1, n-1); //if we find 2 matching we increase length
    else
        return maxx(lcs(X, Y, m, n-1), lcs(X, Y, m-1, n)); //we include and exclude consequently and chose the max of this
}

void lcs_dynamic(int *X, int *Y, int m, int n, FILE *fp)
{
    int tab[m][n];

    for (int i=0; i<m; i++) //initialize all with 0s
    {
        for (int j=0; j<n; j++)
        {
            tab[i][j]=0;
        }
    }

    for(int i=0; i<n; i++) //first row
    {
        if(Y[0]==X[i])
            tab[0][i]=1;
    }
    for(int i=0; i<m; i++)  //first column
    {
        if(X[0]==Y[i])
            tab[i][0]=1;
    }
    for (int i=1; i<m; i++)
    {
        for (int j=1; j<n; j++)
        {
            if (X[i]==Y[j])
            {
                tab[i][j]=1+tab[i-1][j-1];
            }
            else tab[i][j]=maxx(tab[i][j-1], tab[i-1][j]);
        }
    }

    int arr[100]={0}; int index=tab[m-1][n-1];

    int i=m, j=n;
    while(i>0 && j>0)
    {
        if(X[i-1]==Y[j-1])
        {
            arr[index-1]=X[i-1];
            i--, j--, index--;
        }
        else if(tab[i-1][j]>tab[i][j-1])
            i--;
        else j--;
    }

   fprintf(fp, "%d\n", tab[m-1][n-1]);
    for(int i=0; i<tab[m-1][n-1]; i++)
        fprintf(fp, "%d ", arr[i]);


}

int main()
{
   /*
    int a[10]={1, 2, 3, 1, 7};
    int b[10]={1, 2, 6, 3, 1, 9};
    printf("\n%d", lcs_dynamic(a, b, 5, 6));
    */
    FILE *fin=fopen("cmlsc.in", "r");
    FILE *fout=fopen("cmlsc.out", "w");
    int m, n;
    fscanf(fin, "%d %d", &m, &n);
    int a[m], b[n]; int temp;
    for(int i=0; i<m; i++)
    {
        fscanf(fin, "%d", &temp);
        a[i]=temp;
    }
    for(int i=0; i<n; i++)
    {
        fscanf(fin, "%d", &temp);
        b[i]=temp;
    }
    lcs_dynamic(a, b, m, n, fout);
    return 0;
}