#include <cstdio>
#include <vector>

#define dmax 1025

using namespace std;

int a[dmax], b[dmax], c[dmax][dmax], n, m;

void read()
{
    freopen("cmlsc.in", "r", stdin);
    freopen("cmlsc.out", "w", stdout);

    scanf("%i %i", &n, &m);
    for(int i=1; i<=n; i++)
        scanf("%i", &a[i]);
    for(int i=1; i<=m; i++)
        scanf("%i", &b[i]);

}

int main()
{

    read();
    for(int i=1; i<=n; i++)
        for(int j=1; j<=m; j++)
        {
            if(a[i]==b[i])
                c[i][j]=c[i-1][j-i]+1;
            else
            c[i][j]=max(c[i-1][j], c[i][j-1]);
        }

    printf("%i \n",c[n][m]);

    return 0;
}