#include <bits/stdc++.h>

using namespace std;

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

vector <int> G[16005];

int c[16005], dp[16005];

int n, sol, x, y;

bool viz[16005];

void dfs (int nod)
{
    viz[nod] = true;

    for (int i = 0; i < G[nod].size(); i++)
    {
        if (!viz[G[nod][i]])
        {
            dfs(G[nod][i]);
        }
    }

    dp[nod] = c[nod];
    for (int i = 0; i < G[nod].size(); i++)
    {
        if (dp[G[nod][i]] > 0) dp[nod] += dp[G[nod][i]];
    }
    sol = max(sol, dp[nod]);
}
int main()
{
    f >> n;

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

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

    dfs(1);

    g << sol << '\n';
    return 0;
}