#include <bits/stdc++.h>
using namespace std;
void dfs(vector<long long> &dp0, vector<long long> &dp1, vector<vector<int>> &c, vector<int> &a, vector<int> &b, int v = 0){
  for (int w : c[v]){
    dfs(dp0, dp1, c, a, b, w);
  }
  dp0[v] = a[v];
  for (int w : c[v]){
    dp0[v] += max(dp0[w], dp1[w]);
  }
  dp1[v] = 0;
  for (int w : c[v]){
    dp1[v] += max(dp0[w], dp1[w] + b[v] + b[w]);
  }
}
int main(){
  int N;
  cin >> N;
  vector<int> a(N);
  for (int i = 0; i < N; i++){
    cin >> a[i];
  }
  vector<int> b(N);
  for (int i = 0; i < N; i++){
    cin >> b[i];
  }
  vector<vector<int>> E(N);
  for (int i = 0; i < N - 1; i++){
    int u, v;
    cin >> u >> v;
    u--;
    v--;
    E[u].push_back(v);
    E[v].push_back(u);
  }
  vector<int> p(N, -1);
  vector<vector<int>> c(N);
  queue<int> Q;
  Q.push(0);
  while (!Q.empty()){
    int v = Q.front();
    Q.pop();
    for (int w : E[v]){
      if (w != p[v]){
        p[w] = v;
        c[v].push_back(w);
        Q.push(w);
      }
    }
  }
  vector<long long> dp0(N);
  vector<long long> dp1(N);
  dfs(dp0, dp1, c, a, b);
  cout << max(dp0[0], dp1[0]) << endl;
}