// https://www.lanqiao.cn/problems/19704/learning/?page=1&first_category_id=1&name=%E5%9B%A2%E5%BB%BA
#include <bits/stdc++.h>

#define N 200020
using namespace std;
typedef long long ll;
ll n, m, ans = 0;
vector<ll> t1v(N), t2v(N); // value[]
map<ll, vector<ll>> tree1, tree2; // id, list[]

void dfs(ll x, ll y, ll cnt) {
	if (t1v[x] != t2v[y]) return;
	ans = max(ans, cnt + 1);
	for (int i = 0; i < tree1[x].size(); i++)
		for (int j = 0; j < tree2[y].size(); j++)
			dfs(tree1[x][i], tree2[y][j], cnt + 1);
}

int main() {
	cin >> n >> m;
	for (int i = 1; i <= n; i++) cin >> t1v[i];
	for (int i = 1; i <= m; i++) cin >> t2v[i];
	for (int i = 1; i < n; i++) {
		ll u, v;
		cin >> u >> v;
		tree1[u].push_back(v);
	}
	for (int i = 1; i < m; i++) {
		ll p, q;
		cin >> p >> q;
		tree2[p].push_back(q);
	}
	dfs(1, 1, 0);
	cout << ans << endl;
	return 0;
}