#include <fstream>
#include <vector>
#define MAX 16000
#define INF 1000000000
using namespace std;
ifstream cin ("asmax.in");
ofstream cout ("asmax.out");
int v[MAX + 10], vis[MAX + 10], dp[MAX + 10], ans = -INF;
vector <int> graph[MAX + 10];
void dfs(int node)
{
    vis[node] = 1;
    dp[node] = v[node];
    for (const auto &next : graph[node])
        if (vis[next] == 0)
        {
            dfs(next);
            dp[node] = dp[node] + max(0, dp[next]);
        }
    ans = max(ans, dp[node]);
}
int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> v[i];
    for (int i = 1; i < n; i++)
    {
        int x, y;
        cin >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    dfs(1);
    cout << ans;
    return 0;
}