#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using Edge = pair<int, ll>;

constexpr char newl = '\n';
constexpr ll INF = 1e18;

ll solve(int cur, int par, bool root_used, const vector<ll>& a, const vector< vector<Edge> >& g, vector< vector<ll> >& dp) {
    if (dp[root_used][cur] > -INF) return dp[root_used][cur];
    
    ll res = (root_used ? 0 : a[cur]);
    for (const Edge& e : g[cur]) {
        if (e.first == par) continue;
        res += max(solve(e.first, cur, false, a, g, dp), solve(e.first, cur, true, a, g, dp) + (root_used ? e.second : 0));
    }
    return dp[root_used][cur] = res;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    vector<ll> a(n), b(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    for (int i = 0; i < n; i++) {
        cin >> b[i];
    }

    vector< vector<Edge> > g(n);
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        --u; --v;

        ll score = b[u] + b[v];
        g[u].emplace_back(v, score);
        g[v].emplace_back(u, score);
    }

    vector< vector<ll> > dp(2, vector<ll>(n, -INF));
    cout << max(solve(0, -1, true, a, g, dp), solve(0, -1, false, a, g, dp)) << newl;
    return 0;
}