#include<iostream>
#include<fstream>
using namespace std;
ifstream f("cmlsc.in");
ofstream g("cmlsc.out");
short a[1025],b[1025],m,n,j,i;
int d[1025][1025];
int main()
{
    f>>n>>m;
    for(i=1;i<=n;i++,f>>a[i]);
    for(i=1;i<=m;i++,f>>b[i]);
    for (i=1;i<=n;i++)
        for (j=1;j<=m;j++)
        {
            if (a[i]==b[j])
                    d[i][j]=d[i-1][j-1]+1;
            else d[i][j]=max(d[i-1][j],d[i][j-1]);
        }
    g<<d[n][m];
    g.close();
    f.close();
return 0;
}