#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

ll A[100010];
ll B[100010];
vector<int> E[100010];

struct Node {
  ll value_0;
  ll value_1;

  Node(ll value_0 = -1, ll value_1 = -1) {
    this->value_0 = value_0;
    this->value_1 = value_1;
  }
};

Node t_dp(int v, int parent = -1) {
  int child_num = E[v].size();
  vector<vector<ll>> dp(child_num + 1, vector<ll>(2, LLONG_MIN));
  dp[0][0] = 0LL;
  dp[0][1] = 0LL;

  int i = 0;
  for (int j = 0; j < child_num; ++j) {
    int u = E[v][j];
    if (u == parent) continue;

    Node node = t_dp(u, v);
    // fprintf(stderr, "u: %d, v0: %lld, v1: %lld\n", u, node.value_0, node.value_1);
    dp[i + 1][0] = max(dp[i + 1][0], dp[i][0] + node.value_0);
    dp[i + 1][0] = max(dp[i + 1][0], dp[i][0] + node.value_1 - (B[u]));
    dp[i + 1][1] = max(dp[i + 1][1], dp[i][1] + node.value_0);
    dp[i + 1][1] = max(dp[i + 1][1], dp[i][1] + node.value_1 + B[v]);
    // fprintf(stderr, "dp - v0: %lld, v1: %lld\n", dp[i + 1][0], dp[i + 1][1]);

    ++i;
  }

  if (parent != -1) {
    if (i == 0) {
      return Node(A[v], B[v]);
    } else {
      // fprintf(stderr, "A: %lld, B: %lld\n", A[v], B[v]);
      return Node(dp[i][0] + A[v], dp[i][1] + B[v]);
    }
  } else {
    return Node(dp[i][0] + A[v], dp[i][1]);
  }
}

int main() {
  int N;
  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;
    E[u].push_back(v);
    E[v].push_back(u);
  }

  Node node = t_dp(0, -1);
  cout << max(node.value_0, node.value_1) << endl;

  return 0;
}