#include <iostream>
#include <fstream>
#include <vector>
#define VVI vector <vector <int> >
using namespace std;

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

void Citire();
void Dfs(int nod);

int n;
int cost[16001];
bool vizitat[16001];

VVI G;

int main()
{
    Citire();
    Dfs(1);
    int maxim = -0x3f3f3f3f;
    for (int i = 1; i <= n; ++i)
        maxim = max(maxim, cost[i]);

    fout << maxim;
}

void Dfs(int nod)
{
    vizitat[nod] = true;
    for (int i = 0; i < G[nod].size(); ++i)
    {
        int vecin = G[nod][i];
        if (!vizitat[vecin])
        {
            Dfs(vecin);
            cost[nod] = max(cost[nod], cost[nod] + cost[vecin]);
        }
    }
}
void Citire()
{
    fin >> n;
    G = VVI(n + 1);
    for (int i = 1; i <= n; ++i)
        fin >> cost[i];
    int x, y;
    for (int j = 1; j < n; ++j)
    {
        int x, y;
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}