#include <bits/stdc++.h>

using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
int n, maxi, t[16005], a[16005];
bool viz[16005];
vector<int> G[16005];
void Dfs(int x)
{
    viz[x] = 1;
    a[x] = t[x];
    for(int e : G[x])
        if(viz[e] == 0)
        {
            Dfs(e);
            a[x] += a[e];
        }
    maxi = max(maxi, a[x]);
    if(a[x] < 0) a[x] = 0;
}

int main()
{
    int i, j, x;
    fin >> n;
    for(i = 1;i <= n;i++)
        fin >> t[i];
    for(int ind = 1;ind < n;ind++)
    {
        fin >> i >> j;
        G[i].push_back(j);
        G[j].push_back(i);
    }
    maxi = INT_MIN;
    Dfs(1);
    fout << maxi << "\n";
    fout.close();
    return 0;
}