#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream fin ("asmax.in");
ofstream fout("asmax.out");
int val[16002], dp[16002];
vector<int> a[16002];

void dfs (int x,int tata)
{
    dp[x] = val[x];
    for (int y : a[x])
        if (y != tata)
        {
            dfs(y, x);
            if (dp[y] > 0)
                dp[x] += dp[y];
        }
}

int main () {
    //dp[nod] = valoarea maxima pe care o obtinem intr-un subarbore cu radacina in nod
    int n, x, y, maxim = -1001;
    fin >> n;
    for (int i = 1; i <= n; i++)
        fin >> val[i];
    for (int i = 1; i < n; i++)
    {
        fin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1, 0);
    for (int i = 1; i <= n; i++)
        maxim = max(maxim, dp[i]);
        
    fout << maxim;
}