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

using namespace std;

#define MAXN 16010

ifstream f("asmax.in");
ofstream g("asmax.out");

vector<int> G[MAXN];
int v[MAXN], viz[MAXN], n, x, y, maxim;

void dfs(int nod) {
    viz[nod] = 1;
    for (auto it:G[nod]) {
        if (!viz[it]) {
            dfs(it);
            if (v[it] > 0) {
                v[nod] += v[it];
            }
        }
    }
}

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

    for (int i = 1; i < n; ++i) {
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }

    dfs(1);
    maxim = v[1];

    for (int i = 2; i <= n; ++i) {
        maxim = max(maxim, v[i]);
    }
    g << maxim;

    return 0;
}