#include <iostream>
#include <vector>
#include <fstream>
#define INF 2000000000

using namespace std;

int n, sol;
int cost[16010], best[16010];
vector <int> G[16010];
bool viz[16010];

/// best[i] = costul maxim al unui subarbore cu radacina in nodul i
/// consider ca arborele are radacina in nodul 1

inline void Read()
{
    ifstream f ("asmax.in");
    f>>n;
    int i, x, y;
    for (i=1; i<=n; i++)
        f>>cost[i];
    for (i=1; i<n; i++)
    {
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    f.close();
}

inline void DFS(int nod)
{
    best[nod] = cost[nod];
    viz[nod] = true;
    vector <int>::iterator it;
    for (it = G[nod].begin(); it!=G[nod].end(); it++)
    {
        if (viz[*it] == false)
        {
            DFS(*it);
            best[nod] = max(best[nod], best[nod] + best[*it]);
        }
    }

}

inline void Solve()
{
    DFS(1);
    sol = -INF;
    for (int i = 1; i<=n; i++)
        sol = max (sol, best[i]);
}

inline void Write()
{
    ofstream g("asmax.out");
    g<<sol<<"\n";
    g.close();
}

int main()
{
    Read();
    Solve();
    Write();
    return 0;
}