#include <bits/stdc++.h>
using namespace std;

const int N = 3010;

int a[N], b[N], f[N], n;

int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= n; i++) cin >> b[i];

    for (int i = 1; i <= n; i++) {
        int maxv = 1;
        for (int j = 1; j <= n; j++) {
            if (a[i] == b[j]) f[j] = max(maxv, f[j]);
            if (a[i] > b[j]) maxv = max(f[j] + 1, maxv);
        }
    }

    int res = 0;
    for (int i = 1; i <= n; i++) res = max(res, f[i]);

    cout << res << endl;
    return 0;
}