#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");

const int Nmax=16005;
int Use[Nmax],V[Nmax],Smax[Nmax],N,Sol=-1000;

vector <int> X[Nmax];

void Read()
{
    fin>>N;
    for(int i=1;i<=N;++i)
        fin>>V[i];
    for(int i=1;i<=N-1;++i)
    {
        int x,y;
        fin>>x>>y;
        X[x].push_back(y);
        X[y].push_back(x);
    }
}

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

void Print()
{
    fout<<Sol<<"\n";
}

int main()
{
    Read(); DFS(1); Print();
    return 0;
}