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

int n, m, maxim = -(1<<30), val[16001];
vector<int> gr[16001];
bool viz[16001];

void citire() {
    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);
    }
}

void parcurgere(int nod) {
    for (int i = 0; i < gr[nod].size(); i++)
        if (!viz[gr[nod][i]]) {
            viz[gr[nod][i]] = true;
            parcurgere(gr[nod][i]);
            val[nod] = max(val[nod], val[nod] + val[gr[nod][i]]);
        }
    maxim = max(maxim, val[nod]);
}

int main(int argc, const char * argv[]) {
    citire();
    viz[1] = true;
    parcurgere(1);
    fout << maxim;
}