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

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

int dp[16001];
//dp[i] = suma maxima pe care o pot obtine din subarborele cu radacina i

vector <int> v[16001];
bool ok[16001];
int rasp = -(1<<30);

void dfs(int r)
{
    ok[r] = 1;
    int i;
    for (i = 0; i<v[r].size(); i++)
        if (ok[v[r][i]] == 0)
        {
            dfs(v[r][i]);
            if (dp[v[r][i]] > 0)
                dp[r] += dp[v[r][i]];
        }
    rasp = max(rasp, dp[r]);
}

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