#include <fstream>
#include <array>
#include <vector>
#include <limits>
using namespace std;

std::ifstream in("asmax.in");
std::ofstream out("asmax.out");

const int nmax = 16005;

vector<int> graph[nmax];
array<int, nmax> weight;
array<bool, nmax> visited;

void dfs(int u) {
    visited[u] = true;
    for (auto v : graph[u])
        if (!visited[v]) {
            dfs(v);
            if (weight[v] > 0)
                weight[u] += weight[v];
        }
}

int main() {
    int n;

    in >> n;
    for (int i = 1; i <= n; ++i)
        in >> weight[i];
    for (int i = 1; i < n; ++i) {
        int u, v;
        in >> u >> v;
        graph[u].push_back(v);
        graph[v].push_back(u);
    }
    dfs(1);

    int result = numeric_limits<int>::min();
    for (int i = 1; i <= n; ++i)
        result = max(result, weight[i]);
    out << result << '\n';

    return 0;
}