#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<ll> s(n);
    rep(i, n) cin >> s[i];
    vector<vector<int>> g(n);
    rep(i, n - 1) {
        int a, b;
        cin >> a >> b;
        a--;
        b--;
        if (s[a] > s[b]) {
            g[b].push_back(a);
        } else if (s[a] < s[b]) {
            g[a].push_back(b);
        }
    }
    vector<ll> a(n, -1);
    function<ll(int)> rec = [&](int i) {
        if (a[i] != -1)
            return a[i];
        ll ans = 0;
        for (auto j : g[i]) {
            ans = max(ans, rec(j));
        }
        return a[i] = ans + s[i];
    };
    ll ans = 0;
    rep(i, n) {
        rec(i);
        ans = max(ans, a[i]);
    }
    // rep(i, n) cout << a[i] << " ";
    // cout << endl;
    cout << ans << endl;
    return 0;
}