#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 16007;

vector<vector<int>> v(NMAX);
vector<int> cost(NMAX);
vector<bool> ok(NMAX);
vector<int> dp(NMAX);
int maxim = INT_MIN;

void dfs(int nod)
{
    ok[nod] = true;
    for (auto i: v[nod])
    {
        if (!ok[i])
        {
            dfs(i);
            dp[i] = max(dp[i], dp[i] + dp[nod]);
        }

    }

    dp[nod] += cost[nod];
    maxim = max(maxim, dp[nod]);
}

int main()
{
    int n;
    fin >> n;

    for (int i = 1; i <= n; i++)
        fin >> cost[i];


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

    dfs(1);

    fout << maxim << "\n";
    return 0;
}