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

using namespace std;

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

vector <int> g[16005];
int d[16005], n;
bool viz[16005];

void dfs(int nod){
    viz[nod] = 1;
    for (auto i : g[nod])
        if (!viz[i]){
            dfs(i);
            if (d[i] > 0)
                d[nod] += d[i];
        }
}

int main()
{
    fin >> n;
    for (int i = 1; i <= n; i++)
        fin >> d[i];
    for (int i = 1; i < n; i++){
        int a, b;
        fin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    dfs(1);
    int sol = -16000005;
    for (int i = 1; i <= n; i++)
        if (sol < d[i])
            sol = d[i];
    fout << sol << '\n';
    return 0;
}