#include <bits/stdc++.h>
using namespace std;

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

int n, Max;
int dp[16005], a[16005];
bitset<16005> viz;
vector<int> L[16005];

void DFS(int k)
{
    viz[k] = 1;
    dp[k] = a[k];
    for (int i : L[k])
        if (viz[i] == 0)
        {
            DFS(i);
            dp[k] += dp[i];
        }
    Max = max(Max, dp[k]);
    if (dp[k] < 0) dp[k] = 0;
}
int main()
{
    int i, x, y;
    fin >> n;
    for (i = 1; i <= n; i++)
        fin >> a[i];
    for (i = 1; i < n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    Max = INT_MIN;
    DFS(1);
    fout << Max << "\n";
    return 0;
}