/* -*- coding: utf-8 -*-
 *
 * 1221.cc:  No.1221 木 *= 3 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100000;
const long long LINF = 1LL << 62;

/* typedef */

typedef long long ll;
typedef vector<int> vi;
typedef queue<int> qi;

/* global variables */

int as[MAX_N], bs[MAX_N];
vi nbrs[MAX_N];
int ps[MAX_N], cns[MAX_N];
ll dp[MAX_N][2];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", as + i);
  for (int i = 0; i < n; i++) scanf("%d", bs + i);

  for (int i = 1; i < n; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    u--, v--;
    nbrs[u].push_back(v);
    nbrs[v].push_back(u);
  }

  ps[0] = -1;
  qi q;
  q.push(0);

  while (! q.empty()) {
    int u = q.front(); q.pop();
    int up = ps[u];
    vi &nbru = nbrs[u];
    for (vi::iterator vit = nbru.begin(); vit != nbru.end(); vit++) {
      int v = *vit;
      if (v != up) {
	ps[v] = u;
	cns[u]++;
	q.push(v);
      }
    }
  }

  for (int u = 0; u < n; u++)
    if (cns[u] == 0) q.push(u);

  while (! q.empty()) {
    int u = q.front(); q.pop();
    dp[u][0] += as[u];

    int up = ps[u];
    if (up >= 0) {
      dp[up][0] += max(dp[u][0], dp[u][1]);
      dp[up][1] += max(dp[u][0], dp[u][1] + bs[up] + bs[u]);
      if (--cns[up] == 0) q.push(up);
    }
  }

  printf("%lld\n", max(dp[0][0], dp[0][1]));
  return 0;
}