#include <fstream>
#include <vector>

using namespace std;

ifstream f("asmax.in");
ofstream g("asmax.out");

const int NMAX = 100005;

int n, m, ans = -1000;
int dp[NMAX];

vector <int > L[NMAX];

void citire()
{
    int x, y;
    f >> n;
    for(int i = 1; i <= n; i ++)
        f >> dp[i];
    for(int i = 1; i < n; i ++)
    {
        f >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

void DFS(int node, int tata)
{
    for(auto it : L[node])
    {
        if(it != tata)
        {
            DFS(it, node);
            if(dp[it] > 0)
                dp[node] += dp[it];
        }
    }
    ans = max(ans, dp[node]);
}

int main()
{
    citire();
    DFS(1, 0);
    g << ans << '\n';
    return 0;
}