#include <fstream>
#include <vector>
#include <climits>

using namespace std;

ifstream cin("asmax.in");
ofstream cout("asmax.out");

vector<vector<int>> tree;
vector<int> dp;
int n;

void dfs(int node, int parent) {
    for (int nei : tree[node]) {
        if (nei != parent) {
            dfs(nei, node);
            if (dp[nei] > 0) {
                dp[node] += dp[nei];
            }
        }
    }
}

int main() {
    cin >> n;
    tree.assign(n + 2, vector<int>());
    dp.assign(n + 2, 0);
    for (int i = 1 ; i <= n ; ++i) {
        cin >> dp[i];
    }
    for (int i = 1 ; i <= n - 1 ; ++i) {
        int src, dest; cin >> src >> dest;
        tree[src].push_back(dest);
        tree[dest].push_back(src);
    }
    dfs(1, 0);
    int maxx = INT_MIN;
    for (int i = 1 ; i <= n ; ++i) {
        maxx = max(maxx, dp[i]);
    }
    cout << maxx;
    return 0;
}