#include <bits/stdc++.h>
#define NMAX 16006
using namespace std;

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

int N, dp[NMAX], maxim = -(1 << 30);
vector <int> Muchii[NMAX];

void DFS(int nod, int tata)
{
    for (auto it : Muchii[nod])
    {
        if (it != tata)
        {
            DFS(it, nod);
            if (dp[it] > 0)
                dp[nod] += dp[it];
            maxim = max(maxim, dp[nod]);
        }
    }
}

int main()
{
    fin >> N;
    for (int i = 1; i <= N; ++i)
        fin >> dp[i];
    for (int i = 1; i < N; ++i)
    {
        int a, b;
        fin >> a >> b;
        Muchii[a].push_back(b);
        Muchii[b].push_back(a);
    }
    DFS(1, 0);
    fout << maxim;
    fin.close();
    fout.close();
    return 0;
}