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

using namespace std;

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

const int NMAX = 16001;
int n, val[NMAX], sum[NMAX], valmax = -16000001;
vector <int> ad[NMAX];

void dfs(int nod, int parent)
{
    for (int i = 0; i < ad[nod].size(); ++i)
    {
        int w = ad[nod][i];
        if (w != parent)
        {
            dfs(w,nod);
            if (val[w] > 0)
                val[nod]+=val[w];
        }
    }
    if (val[nod] > valmax) valmax = val[nod];
}

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;
        ad[x].push_back(y);
        ad[y].push_back(x);
    }
    dfs(1,0);
    fout << valmax;
    return 0;
}