#include <bits/stdc++.h>
using namespace std;
ifstream fin ("asmax.in");
ofstream fout("asmax.out");
const int dim = 100002;
int n,v[dim], dp[dim];
bool viz[dim];
vector<int> a[dim];

void dfs (int tata)
{
    dp[tata] = v[tata];
    viz[tata] = 1;
    for (auto fiu : a[tata])
        if (!viz[fiu])
        {
            dfs(fiu);
            if (dp[fiu] > 0)
                dp[tata] += dp[fiu];
        }
}

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

    dfs(1);

    int maxi = 0;
    for (int i = 1; i < n; i++)
        maxi = max(dp[i], maxi);

    fout << maxi;
    return 0;
}