#include <bits/stdc++.h>
using namespace std;

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

const int MAX_NUM = 16005;

int n, answer = INT_MIN;
vector<bool> visited(MAX_NUM, false);
vector<int> graph[MAX_NUM], v(MAX_NUM);

void dfs(int x) {
    visited[x] = true;
    for (int node : graph[x]) {
        if (!visited[node]) {
            dfs(node);
            if (v[node] > 0) {
                v[x] += v[node];
            }
        }
    }
    answer = max(answer, v[x]);
}

int main() {
    fin >> n;
    for (int i = 1; i <= n; ++i) {
        fin >> v[i];
    }
    for (int i = 0; i < n - 1; ++i) {
        int a, b;
        fin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    dfs(1);
    fout << answer;
    return 0;
}