#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cassert>

#define N 5005

using namespace std;

int n, m, a[N], b[N], dp[N][N], res;

int main() {
    freopen("interview.in", "r", stdin);
    freopen("interview.out", "w", stdout);

    cin >> n >> m;
    for (int i = 0; i < n; i++)
        cin >> a[i];

    for (int j = 0; j < m; j++)
        cin >> b[j];

    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++) {
            if (a[i] == b[j]) {
                dp[i][j] = 1;
                for (int k = 0; k < i; k++)
                    for (int t = 0; t < j; t++) {
                        if (a[k] == b[t] && a[k] < a[i]) {
                            dp[i][j] = max(dp[i][j], dp[k][t] + 1);
                        }
                    }
            }
            res = max(dp[i][j], res);
        }

    cout << res << endl;

    return 0;
}