#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}

#define MAX_N 200005
vector<int> pre_G[MAX_N];
vector<int> G[MAX_N];
int par_[MAX_N];
int flag_netsukigi[MAX_N];
void make_netsukigi(int r){
    rep(i,MAX_N){
        G[i].clear();
        par_[i] = 0;
        flag_netsukigi[i] = 0;
    }
    queue<int> que;
    que.push(r);
    flag_netsukigi[r] = 1;
    par_[r] = -1;

    while(que.size() > 0){
        int x = que.front();
        que.pop();
        flag_netsukigi[x] = 1;
        rep(i,pre_G[x].size()){
            if(flag_netsukigi[pre_G[x][i]] == 0){
                par_[pre_G[x][i]] = x;
                G[x].push_back(pre_G[x][i]);
                que.push(pre_G[x][i]);
            }
        }
    }
}

ll dp[MAX_N][2];
ll INF = 1001001001001001001;
int main() {
    int n;
    cin >> n;
    ll a[n], b[n];
    rep(i,n) cin >> a[i];
    rep(i,n) cin >> b[i];

    rep(i,n-1){
        int a, b;
        scanf("%d%d", &a, &b);
        a--; b--; // 0-indexにするため.
        pre_G[a].push_back(b);
        pre_G[b].push_back(a);
    }

    make_netsukigi(0);

    rep(i,n)rep(j,2)dp[i][j] = -INF;

    queue<int> que;
    int son[n] = {};
    rep(i,n){
        son[i] = G[i].size();
        if(son[i] == 0){
            que.push(i);
        }
    }

    while(que.size()){
        int x = que.front();
        que.pop();
        dp[x][0] = a[x];
        dp[x][1] = 0;
        rep(i,G[x].size()){
            int y = G[x][i];
            dp[x][0] += max(dp[y][0], dp[y][1]);
            dp[x][1] += max(dp[y][0], dp[y][1] + b[x] + b[y]);
        }
        if(x == 0)break;
        son[par_[x]]--;
        if(son[par_[x]] == 0) que.push(par_[x]);
    }

    cout << max(dp[0][0], dp[0][1]) << endl;
    return 0;
}