#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;

int main() {
    int n;
    cin >> n;
    vector<int> A(n), B(n), num(n);
    for (auto &&i : A) scanf("%d", &i);
    for (auto &&i : B) scanf("%d", &i);
    vector<ll> dp1(n, 0), dp2(n, 0);
    vector<vector<int>> G(n);
    for (int i = 0; i < n-1; ++i) {
        int a, b;
        scanf("%d %d", &a, &b);
        a--; b--;
        G[a].emplace_back(b);
        G[b].emplace_back(a);
    }
    deque<int> Q;
    {
        stack<int> s;
        int cnt = 0;
        vector<int> visited(n, 0);
        s.emplace(0);
        while(!s.empty()){
            int a = s.top(); s.pop();
            visited[a]++;
            num[a] = cnt++;
            Q.emplace_front(a);
            for (auto &&i : G[a]) {
                if(!visited[i]) s.emplace(i);
            }
        }
    }
    for (auto &&i : Q) {
        dp1[i] = A[i];
        for (auto &&j : G[i]) {
            if(num[i] < num[j]) {
                dp1[i] += max(dp1[j], dp2[j]);
                dp2[i] += max(dp1[j], dp2[j]+B[i]+B[j]);
            }
        }
    }
    cout << max(dp1[0], dp2[0]) << "\n";
    return 0;
}