#include<fstream>
#include <vector>
#include<iostream>
#include<climits>
#define NMAX 16001

using namespace std;

ifstream fin("asmax.in");
ofstream fout("asmax.out");
int k, n, marc[NMAX], cost[NMAX], maxcost[NMAX];

vector <int> vecini[NMAX];

void citire() {
    int i, x, y;
    fin >> n;
    for (i = 1; i <= n; i++) {
        fin >> cost[i];
        maxcost[i] = cost[i];
        marc[i] = 0;
    }
    for (i = 1; i <= n - 1; i++) {
        fin >> x >> y;
        vecini[x].push_back(y);
        vecini[y].push_back(x);
    }
    fin.close();
}

void afis() {
    int i;
    for (i = 1; i <= n; i++)
        fout << maxcost[i] << " ";
    fout << endl;
}

void dfs(int p) {
    int i, y;
    marc[p] = 1;
    maxcost[p] = cost[p];
    for (i = 0; i < vecini[p].size(); i++) {
        y = vecini[p][i];
        if (not marc[y]) {
            dfs(y);
            if (maxcost[y] > 0)
                maxcost[p] += maxcost[y];
        }
    }
}

int calcmaxcost() {
    int maxi = INT_MIN;
    for (int i = 1; i <= n; i++)
        if (maxcost[i] > maxi)
            maxi = maxcost[i];
    return maxi;
}

int main() {
    citire();
    //afis();
    for (k = 1; k <= n; k++)
        if (not marc[k])
            dfs(k);
    //afis();
    fout << calcmaxcost();
    fout.close();
    return 0;
}