#include <iostream>
#include <fstream>
#include <vector>
#define MAX 16001

using namespace std;

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

bool viz[MAX];
int n;
int maxim;
int dp[MAX];

vector <int> edge[MAX];

void read()
{
    fin >> n;
    fin >> dp[1];
    maxim = dp[1];
    for (int i = 2; i <= n; i++)
    {
        fin >> dp[i];
        if (dp[i] > maxim)
            maxim = dp[i];
    }
    for (int i = 1; i < n; i++)
    {
        int x, y;
        fin >> x >> y;
        edge[x].push_back(y);
        edge[y].push_back(x);
    }
}

void dfs(int nod)
{
    viz[nod] = true;
    for (unsigned int i = 0; i < edge[nod].size(); i++)
    {
        int vecin = edge[nod][i];
        if (!viz[vecin])
        {
            dfs(vecin);
            dp[nod] = max(dp[nod], dp[nod] + dp[vecin]);
        }
        maxim = max(maxim, dp[nod]);
    }
}

int main()
{
    read();
    dfs(1);
    fout << maxim;
    return 0;
}