#include <iostream>
#include <fstream>
#include <vector>
#define NMAX 16005

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

using namespace std;

vector <int> Gr[NMAX];
int n , val[NMAX] , sol[NMAX];

void DFS (int nod , int tata)
{
    sol[nod] = val[nod];
    for(auto it:Gr[nod]){
        if (it != tata)
        {
            DFS(it , nod);
            sol[nod] = max (sol[nod] , sol[nod] + sol[it]);
        }
    }
}

int checkMax()
{
    int _max = sol[1];
    for(int i = 2 ; i <= n ; ++i)
        _max = max(_max , sol[i]);
    return _max;
}

int main()
{
    fin >> n;
    for(int i = 1 ; i <= n ; ++i) fin >> val[i];
    for(int i = 1 ; i < n ; ++i){
        int x , y;
        fin >> x >> y;
        Gr[x].push_back(y);
        Gr[y].push_back(x);
    }
    DFS (1 , 0);
    fout << checkMax();
    return 0;
}