#include <bits/stdc++.h>

using namespace std;

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

vector <int> L[16005];
int dp[16005], val[16005], n; /// dp[i] = suma maxima din subarborele lui i;
bitset <16005> viz;

void Read()
{
    fin >> n;
    for (int i = 1; i <= n; i++)
        fin >> val[i];
    for (int i = 1; i < n; i++)
    {
        int x, y;
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

void DFS(int nod)
{
    viz[nod] = 1;
    dp[nod] = val[nod];
    for (auto next : L[nod])
        if (!viz[next])
        {
            DFS(next);
            if (dp[next] > 0)
                dp[nod] += dp[next];
        }
}

void Solve()
{
    DFS(1);
    int maxsum = -2e9;
    for (int i = 1; i <= n; i++)
        maxsum = max(maxsum, dp[i]);
    fout << maxsum;
}

int main()
{
    Read();
    Solve();
    return 0;
}