#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>

using namespace std;
typedef long long ll;

int N;
ll a[100000];
ll b[100000];
bool used[100000];

vector<int> G[100000];
// dp1残す、dp2残さない
ll dp1[100000], dp2[100000];

const ll INF = 1e18;

void dfs(int v){
    used[v] = true;
    dp2[v] = a[v];
    ll max1 = -INF, max2 = -INF;
    for(int to : G[v]){
        if(!used[to]){
            dfs(to);
            dp1[v] += max(dp1[to]+b[to]+b[v], dp2[to]);
            dp2[v] += max(dp1[to], dp2[to]);
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    cin >> N;
    for(int i = 0;i < N; i++) cin >> a[i];
    for(int i = 0;i < N; i++) cin >> b[i];
    for(int i = 0; i < N-1; i++){
        int u, v; cin >> u >> v; u--; v--;
        G[u].push_back(v);
        G[v].push_back(u);
    }
    dfs(0);
    cout << max(dp1[0], dp2[0]) << endl;
}