#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

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

const int NMAX = 16000;
int n, V[NMAX+1], D[2][NMAX+1];

vector<int> G[NMAX+1];

void citire() {
    f >> n;
    for (int i=1; i<=n; i++)
        f >> V[i];

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

void DFS(int nod, int tata) {
    D[1][nod] = V[nod];
    D[0][nod] = 0;
    //
    for (const auto &x : G[nod])
        if (x != tata) {
            DFS(x, nod);

            D[1][nod] += max(D[1][x], 0);
            D[0][nod] = max(D[0][nod], max(D[0][x], D[1][x]));
        }
}

int main(){
    citire();
    DFS(1, 0);
    g << max(D[1][1], D[0][1]);
    //
    f.close();
    g.close();
    return 0;
}