#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
const int NMax = 16005;
const int oo = -10000000;
vector <int> G[NMax];
int N, sol = oo;
int V[NMax], DP[NMax];
bool Use[NMax];
void Read()
{
    in >> N;
    for(int i = 1;i<=N;++i)
        in >> V[i];
    for(int i = 1;i<=N-1;++i)
    {
        int x,y;
        in >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void DFS(int Nod)
{
    Use[Nod] = 1;
    DP[Nod] = V[Nod];
    for(int i=0;i<(int)G[Nod].size();++i)
    {
        int Vecin = G[Nod][i];
        if(Use[Vecin] == 0)
        {
            DFS(Vecin);
            DP[Nod] = max(DP[Nod],DP[Nod]+DP[Vecin]);
        }
    }
}

void Solve()
{
    for(int i = 1;i<=N;++i)
        sol=max(sol,DP[i]);
    out<<sol;
}
int main()
{
    Read();
    DFS(1);
    Solve();
    return 0;
}