#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

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

int n;
vector <int> graph[16005];
int val[16005];
bool visited[16005];

int maxSum = -100000;

int bkt(int node)
{
    int sum = val[node];
    visited[node] = true;

    for (int x : graph[node])
    {
        if (!visited[x])
        {
            visited[x] = true;
            int newSum = bkt(x);

            if (newSum > 0)
            {
                sum += newSum;
            }
        }
    }

    if (sum > maxSum) maxSum = sum;
    return sum;
}

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

    for (int i = 0; i < n - 1; i++)
    {
        int a, b;
        fin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }

    bkt(1);
    fout << maxSum << '\n';
}