#include <bits/stdc++.h>
#define NMAX 20000

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

int n, maxim = -1e9, v[NMAX];
vector <int> G[NMAX];

int DFS(int nod, int tata);

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

int DFS(int nod, int tata)
{
    int s = v[nod];
    for (auto vf : G[nod])
        if (vf != tata)
        {
            int val = DFS(vf, nod);
            if (val > 0)
                s += val;
        }
    maxim = max(maxim, s);
    return s;
}