#include<iostream>
#include<fstream>
using namespace std;

ifstream f("cmlsc.in");
ofstream g("cmlsc.out");

short x[1030],y[1030],a[1030][1030], d[1030];;
short m,n;

void citire()
{
short i,j;
f>>n>>m;
for(i=1;i<=n;i++)f>>x[i];
for(i=1;i<=m;i++)f>>y[i];
f.close();
}

void subsirmax()

{ short i,j;
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
if(x[i]==y[j])a[i][j]=1+a[i-1][j-1];
  else a[i][j]=max(a[i-1][j],a[i][j-1]);
g<<(int)a[n][m]<<endl;
}

void scrie(short val)
{short k=0, i=n,j=m;

while(val&&i&&j)
{
if (x[i]==y[j]){ d[++k]=x[i];
  i--; j--;}
else
if(a[i][j]==a[i-1][j])i--;
   else j--;
}
g<<d[k];
for(i=k-1;i>=1;i--) g<<' '<<d[i];

g<<endl;
g.close();
}


int main()
{
citire();
subsirmax();
scrie(a[n][m]);
return 0;
}