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

ifstream fin("asmax.in");
ofstream fout("asmax.out");
vector<int> h[16002];
int M, n, viz[16002];
int a[16002];
int dp[16002]; /// dp[i] = suma maxima care se poate
/// obtine din subarborele cu radacina in i

void Citire()
{
    int i, x, y;
    fin >> n;
    for (i = 1; i <= n; i++)
        fin >> a[i];
    for (i = 1; i < n; i++)
    {
        fin >> x >> y;
        h[x].push_back(y);
        h[y].push_back(x);
    }
}

void DFS(int k)
{
    viz[k] = 1;
    dp[k] = a[k];
    for (int i : h[k])
        if (viz[i] == 0)
        {
            DFS(i);
            if (dp[i] > 0) dp[k] += dp[i];
        }
    ///M = max(M, dp[k]);
}

void Afisare()
{
    int i;
    M = dp[1];
    for (i = 2; i <= n; i++)
        M = max(dp[i], M);
    fout << M << "\n";
}

int main()
{
    Citire();
    DFS(1);
    Afisare();
    fin.close();
    fout.close();
    return 0;
}