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

using namespace std;

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

const int NMax = 16005;

int v[NMax], sol = -NMax, D[NMax];
bool viz[NMax];
vector < int > ad[NMax];

void DFS(int node){
    viz[node] = 1;
    D[node] = v[node];
    for(int i = 0; i < ad[node].size(); i++){
        if(!viz[ad[node][i]]){
            DFS(ad[node][i]);
            if(D[ad[node][i]] > 0){
                D[node] += D[ad[node][i]];
            }
        }
    }
    sol = max(sol, D[node]);
}

int main()
{
    int n, x, y;
    fin >> n;
    for(int i = 1; i <= n; i++){
        fin >> v[i];
    }
    for(int i = 1; i < n; i++){
        fin >> x >> y;
        ad[x].push_back(y);
        ad[y].push_back(x);
    }
    DFS(1);
    fout << sol;
    return 0;
}