#include <bits/stdc++.h>

using namespace std;

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

const int nmax = 16e3 + 5;

vector <int> G[nmax];

bitset <nmax> viz;

int n, sum[nmax], x, y, sol;

void dfs (int nod = 1)
{
    int ver;

    viz[nod] = 1;

    for (int i=0; i<G[nod].size(); ++i)
    {
        ver = G[nod][i];
        if (viz[ver]) continue;
        if (sum[ver] > 0) sum[nod] += sum[ver];
    }
    sol = max(sol, sum[nod]);
}

int main()
{
    fin >> n;
    for (int i=1; i<=n; ++i)
        fin >> sum[i];
    for (int i=1; i<n; ++i)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs();
    fout << sol;
    return 0;
}