#include <bits/stdc++.h>
using namespace std;
#define rep2(i,m,n) for (int i = (m); i < (n); ++i)
#define rep(i,n) rep2(i,0,n)
#define debug(x) cerr << x << endl
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> P;
template<typename T> struct V : vector<T> { using vector<T>::vector; };
V() -> V<int>;
V(size_t) -> V<int>;
template<typename T> V(size_t, T) -> V<T>;
template<typename T> vector<T> make_vec(size_t n, T a) { return vector<T>(n, a); }
template<typename... Ts> auto make_vec(size_t n, Ts... ts) { return vector<decltype(make_vec(ts...))>(n, make_vec(ts...)); }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; }
struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }
template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
const int INF = 1<<30;
const ll LINF = 1LL<<61;
const ll MOD = 1000000007;

int main()
{
    int n;
    cin >> n;
    V<ll> a(n), b(n);
    rep(i,n) cin >> a[i];
    rep(i,n) cin >> b[i];
    auto G = make_vec(n, 0, 0);
    rep(i,n-1)
    {
        int u, v;
        cin >> u >> v;
        --u; --v;
        G[u].emplace_back(v);
        G[v].emplace_back(u);
    }
    //dp[i][j] := i以下の部分木だけを考慮したときの最大スコア, j==1 <=> i番目の頂点は残っている
    auto dp = make_vec(n+1, 2, -LINF);
    auto rec = [&](auto self, int v, int pv, bool is_include) -> ll
    {
        if(dp[v][is_include] != -LINF)
        {
            return dp[v][is_include];
        }
        ll res = 0;
        for(auto w:G[v])
        {
            if(w == pv) continue;
            self(self, w, v, 0);
            self(self, w, v, 1);
        }
        if(is_include)
        {
            for(auto w:G[v])
            {
                if(w == pv) continue;
                res += max(b[w]+b[v]+dp[w][1], dp[w][0]);
            }
        }
        else
        {
            res += a[v];
            for(auto w:G[v])
            {
                if(w == pv) continue;
                res += max(dp[w][1], dp[w][0]);
            }
        }
        dp[v][is_include] = res;
        return res;
    };
    ll ans = max(rec(rec, 0, -1, 0), rec(rec, 0, -1, 1));
    cout << ans << endl;

    return 0;
}