#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

const int NMAX = 16000 + 5;
const int INF = 0x3f3f3f3f;

vector <int> arb[NMAX];
int n;
int v[NMAX], dp[NMAX];
bool vis[NMAX];

void dfs(int node)
{
    vis[node] = true;
    dp[node] = v[node];

    for (int i: arb[node])
        if (!vis[i])
        {
            dfs(i);
            dp[node] += max(dp[i], 0);
        }
}

void write()
{
    int maxim = -INF;
    for (int i = 1; i <= n; ++i)
        maxim = max(maxim, dp[i]);
    fout << maxim;
}

void read()
{
    int x, y;

    fin >> n;
    for (int i = 1; i <= n; ++i)
        fin >> v[i];
    for (int i = 1; i < n; ++i)
    {
        fin >> x >> y;
        arb[x].push_back(y);
        arb[y].push_back(x);
    }
}

int main()
{
    read();
    dfs(1);
    write();

    return 0;
}