#include <iostream>
#include <fstream>
#include <vector>

using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");

const int Nmax = 16005 , oo = -100000000;
int n, m, cost[Nmax], sol = oo, Sum[Nmax];
vector <int> G[Nmax];

void Print()
{
    g<<sol<<'\n';
}

void Solve(int nod, int tata)
{
    for(int i = 0; i <(int) G[nod].size(); i++)
    {
        int Vecin = G[nod][i];
        if(Vecin != tata)
        {
            Solve(Vecin, nod);
        }
    }
    if(Sum[nod] + cost[nod] > 0) Sum[tata] += Sum[nod] + cost[nod];
}

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

int main()
{
    Read();
    Solve(1,0);
    for(int i = 1; i <= n; i++)
    {
        if(Sum[i] + cost[i] > sol) sol = Sum[i] + cost[i];
    }
    Print();
    return 0;
}