#include <iostream>
#include <bits/stdc++.h>

#define inf 1e9

using namespace std;

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

int n;
int valori[16001];
vector<int> la[16001];
int viz[16001];
int max_in_node[16001];

int get_max(int from)
{
    if (max_in_node[from] != -inf)
        return max_in_node[from];

    viz[from] = 1;

    int mx = valori[from];
    for (auto& to: la[from])
    {
        if (viz[to])
            continue;
        mx += get_max(to);
    }

    viz[from] = 0;

    int ret = max(mx, 0);
    max_in_node[from] = ret;
    return ret;
}

int main()
{
    in >> n;
    for (int i = 1; i <= n; i++)
    {
        in >> valori[i];
        max_in_node[i] = -inf;
    }

    for (int i = 1; i < n; i++)
    {
        int from, to;
        in >> from >> to;
        la[from].push_back(to);
        la[to].push_back(from);
    }

    int res = -inf;
    for (int i = 1; i <= n; i++)
    {
        res = max(res, get_max(i));
    }

    out << res;

    return 0;
}