#include <bits/stdc++.h>

const int NMAX = 16005;

std::vector<int> dp(NMAX);
std::vector<int> graph[NMAX];

void DFS(int node, int parent) {
    for (int neighbour : graph[node]) {
        if (neighbour != parent) {
            DFS(neighbour, parent);

            if (dp[neighbour] > 0) {
                dp[node] += dp[neighbour];
            }
        }
    }
}

int main() {
    std::ifstream fin("asmax.in");
    std::ofstream fout("asmax.out");

    int n;
    fin >> n;

    for (int i = 1; i <= n; i++) {
        fin >> dp[i];
    }

    for (int i = 1; i <= n-1; i++) {
        int a, b;
        fin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }

    DFS(1, -1);

    fout << *std::max_element(dp.begin() + 1, dp.end()) << '\n';
    return 0;
}