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

int main() {
    ifstream fin("asmax.in");
    ofstream fout("asmax.out");
    int n;
    fin >> n;

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

    vector<vector<int>> adj(n + 1);
    vector<int> in_degree(n + 1);
    for (int i = 1, x, y; i < n; ++i) {
        fin >> x >> y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    
    int sol = 0;
    
    function<void(int, int)> dfs = [&](int nod, int parinte) -> void {
        dp[nod] = v[nod];
        for (int vec : adj[nod]) {
            if (vec != parinte) {
                dfs(vec, nod);
                if (dp[vec] > 0) {
                    dp[nod] += dp[vec];
                }
            }
        }
        sol = max(sol, dp[nod]);
    };
    dfs(1, 0);

    fout << sol << '\n';


    return 0;
}