#include <fstream>
#include <vector>

using namespace std;

ifstream cin("asmax.in");
ofstream cout("asmax.out");

vector <int> G[16001];

int n, x, y, viz[16001], v[16001], scor[16001], maxi;

void dfs(int x)
{
    viz[x] = 1;
    scor[x] = v[x];
    for (auto y:G[x])
    {
        if (!viz[y])
        {
            dfs(y);
            if (scor[y] > 0)
            {
                scor[x] += scor[y];
            }
        }
    }
}

int main()
{
    cin >> n;
    for (int i=1; i<=n; i++)
    {
        cin >> v[i];
    }
    for (int i=1; i<n; i++)
    {
        cin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1);
    maxi = scor[1];
    for (int i=2; i<=n; i++)
    {
        maxi = max(maxi, scor[i]);
    }
    cout << maxi;
    return 0;
}