#include <iostream>
#include <fstream>
#include <vector>
#include <climits>

using namespace std;

const int nMax = 16005;
vector<int> listaAd[nMax];
int val[nMax], viz[nMax], n, maxSum = -INT_MAX;

int dfsSum(int x) {
    viz[x] = 1;
    int sumX = val[x];

    for (auto y: listaAd[x]) {
        if (!viz[y]) {
            int sumY = dfsSum(y);
            if (sumY > 0) {
                sumX += sumY;
            }
        }
    }
    maxSum = max(maxSum, sumX);
    return sumX;
}

int main() {
    // Solutie: calculam recursiv (in DFS) sumaMax[nod] = val[nod] + sumaMax[fiecare vecin].
    // Daca suma unui vecin este negativa, nu o adaugam la suma nodului curent. Rezultatul
    // e suma maxima gasita a oricarui nod.
    //
    // E obligatoriu sa includem val[nod] in sumaMax[nod], fiindca vrem sa obtinem un arbore
    // (deci nu putem sa sarim noduri).

    // Input rapid
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    ifstream in("asmax.in");
    ofstream out("asmax.out");

    // Input
    in >> n;
    for (int i = 1; i <= n; i++) {
        in >> val[i];
    }
    for (int i = 1; i <= n - 1; i++) {
        int x, y;
        in >> x >> y;
        listaAd[x].push_back(y);
        listaAd[y].push_back(x);
    }

    dfsSum(1);
    out << maxSum;

    return 0;
}