#include <bits/stdc++.h>
using namespace std;
 
int main() {
    int n, m;
    cin >> n >> m;
    vector<int> a(n), b(m);
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int j = 0; j < m; j++) cin >> b[j];
 
    vector<int> dp(m, 0); // dp[j] = LCIS kết thúc tại b[j]
    for (int i = 0; i < n; i++) {
        int current_max = 0;
        for (int j = 0; j < m; j++) {
            if (a[i] == b[j]) {
                dp[j] = max(dp[j], current_max + 1);
            }
            if (a[i] > b[j]) {
                current_max = max(current_max, dp[j]);
            }
        }
    }
 
    cout << *max_element(dp.begin(), dp.end()) << "\n";
}
 

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