// Source: https://usaco.guide/general/io

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

const int NMAX = 16000;
int dp[NMAX + 1];
int v[NMAX + 1];
vector<int> L[NMAX + 1];

void dfs(int node, int tata) {
    dp[node] = v[node];
    for(auto fiu : L[node]) {
        if(fiu != tata) {
            dfs(fiu, node);
            dp[node] += max(0, dp[fiu]);
        }
    }
}

int main() {
    ifstream cin("asmax.in");
    ofstream cout("asmax.out");
	int n;
    cin >> n;
    for(int i = 1; i <= n; i++) {
        cin >> v[i];
    }
    for(int i = 1; i < n; i++) {
        int x, y;
        cin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1, 0);
    int sol = -1000;
    for(int i = 1; i <= n; i++) {
        sol = max(sol, dp[i]);
    }
    cout << sol;
}