#include <bits/stdc++.h>
using namespace std;

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

const int N_MAX = 16000, INF = 2e9;

int n;
int val[N_MAX + 2];
vector<int> gr[N_MAX + 2];

int ans;
int sum[N_MAX + 2];

void dfs(int node, int daddy)
{
    sum[node] = val[node];

    for(auto it: gr[node])
        if(it != daddy)
        {
            dfs(it, node);

            if(sum[it] > 0)
                sum[node] += sum[it];
        }
}

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

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

    dfs(1, 0);

    ans = -INF;
    for(int i = 1; i <= n; i++)
        ans = max(ans, sum[i]);

    out << ans << '\n';

    return 0;
}