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

using namespace std;

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

vector<int> L[16005];
int n, sol = INT_MIN, val[16005], max_sum[16005];

void dfs(int node, int father)
{
    max_sum[node] = val[node];
    for(int son : L[node])
    {
        if(son != father)
        {
            dfs(son, node);
            if(max_sum[son] > 0)
                max_sum[node] += max_sum[son];
        }
    }
}


int main()
{
    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;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1, 0);
    for(int i = 1; i <= n; i++)
        sol = max(sol, max_sum[i]);
    fout << sol;
    return 0;
}