#include <bits/stdc++.h>
//#include <chrono>
//#pragma GCC optimize("Ofast")
using namespace std;
#define reps(i,s,n) for(int i = s; i < n; i++)
#define rep(i,n) reps(i,0,n)
#define Rreps(i,n,e) for(int i = n - 1; i >= e; --i)
#define Rrep(i,n) Rreps(i,n,0)
#define ALL(a) a.begin(), a.end()
#define fi first
#define se second
typedef long long ll;
typedef vector<ll> vec;
typedef vector<vec> mat;

ll N,M,H,W,Q,K,A,B;
string S;
typedef pair<ll, ll> P;
const ll INF = (1LL<<60);

void dfs(int v, int p, mat &G, vec &a, vec &b, vec &r, vec &e){
    e[v] += a[v];
    for(auto to : G[v]){
        if(to != p){
            dfs(to, v, G, a, b, r, e);
            e[v] += max(r[to], e[to]);
            r[v] += max(b[v] + b[to] + r[to], e[to]);
        }
    }
}

int main() {
    cin>>N;
    mat G(N, vec(0));
    vec a(N), b(N), r(N, 0), e(N, 0);
    rep(i,N) cin>>a[i];
    rep(i,N) cin>>b[i];
    rep(i, N - 1){
        int u, t;
        cin>>u>>t;
        --u; --t;
        G[u].push_back(t);
        G[t].push_back(u);
    }
    dfs(0, -1, G, a, b, r, e);
    cout<<max(r[0], e[0])<<endl;
}