#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 100005;

int n, m, ans;
int dp[NMAX];

vector <int > L[NMAX];

void read()
{
    int x, y;
    fin >> n;
    for(int i = 1; i <= n; i ++)
        fin >> dp[i];


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

void dfs(int node, int tata)
{
    for(auto it : L[node])
    {
        if(it != tata)
        {
            dfs(it, node);
            if(dp[it] > 0)
                dp[node] += dp[it];
        }
    }
    ans = max(ans, dp[node]);
}

int main()
{
    read();
    dfs(1, 0);
    fout << ans << '\n';
    return 0;
}