#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

int n, viz[16001], v[16001], sum[16001], maxim = -2e9;
vector<int> gf[16001];

void dfs(int x) {
    viz[x] = 1;
    sum[x] = v[x];
    for (auto vecin : gf[x])
        if (!viz[vecin]) {
            dfs(vecin);
            // dupa ce parcurgem dfs si revin din fiecare fiu
            if (sum[vecin] > 0)
                sum[x] += sum[vecin];
        }
    maxim = max(maxim, sum[x]);
}

int main()
{
    fin >> n;
    for (int i = 1; i <= n; i++) {
        fin >> v[i];
        maxim = max(maxim, v[i]);
    }
    for (int i = 1; i <= n - 1; i++) {
        int x, y;
        fin >> x >> y;
        gf[x].push_back(y);
        gf[y].push_back(x);
    }
    dfs(1);
    fout << maxim;
    return 0;
}