#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <vector>
using namespace std;
using ll = int64_t;
#define rep(i, j, n) for (int i = j; i < (int)n; ++i)


int main() {
  int n;
  cin >> n;
  vector<ll> a(n), b(n);
  rep(i, 0, n) cin >> a[i];
  rep(i, 0, n) cin >> b[i];
  vector<vector<int>> g(n);
  vector<ll> con(n);
  rep(i, 0, n - 1) {
    int u, v;
    cin >> u >> v;
    --u, --v;
    g[u].push_back(v);
    g[v].push_back(u);
    con[u]++;
    con[v]++;
  }

  ll all = 0;
  rep(i, 0, n) all += con[i] * b[i];

  vector<bool> deleted(n);
  rep(i, 0, n) {
    ll add = a[i];
    for (int j : g[i]) {
      if (!deleted[j]) { add -= b[i] + b[j]; }
    }
    if (add > 0) {
      all += add;
      deleted[i] = true;
    }
  }
  cout << all << '\n';

  return 0;
}