#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 maxi = -inf;

int get_max(int from)
{
    viz[from] = 1;

    int mx = valori[from];
    for (auto& to: la[from])
    {
        if (viz[to])
            continue;
        mx += max(0, get_max(to));
    }

    maxi = max(maxi, mx);
    return mx;
}

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

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

    get_max(1);

    out << maxi;

    return 0;
}