#include <bits/stdc++.h>

using namespace std;

const int NMAX = 16005;

vector<int> val(NMAX), dp(NMAX);
vector<int> adj[NMAX];

void parcurgere(int v, int parent) {
    for (auto x : adj[v]) {
        if (x != parent) {
            parcurgere(x, v);
            if (dp[x] > 0) {
                dp[v] += dp[x];
            }
        }
    }
}

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

    int n;
    fin >> n;

    for (int i = 1; i <= n; i++)
        fin >> val[i];

    vector<vector<int>> adj(n+1);
    for (int i = 1; i <= n-1; i++) {
        int a, b;
        fin >> a >> b;

        adj[a].push_back(b);
        adj[b].push_back(a);
    }

    parcurgere(1, -1);

    int solutie = INT_MIN;
    for (int i = 1; i <= n; i++)
        solutie = max(solutie, dp[i]);

    fout << solutie << "\n";
    return 0;
}