#include <iostream>
#include <fstream>
#include <vector>
#define NMAX 16005
#define INF 0x3f3f3f3f
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");

int n, Smax = -INF;
int val[NMAX], viz[NMAX], dp[NMAX];
vector <int> v[NMAX];

void dfs(int nod)
{
    viz[nod] = 1;
    vector <int> :: iterator it;
    for (it = v[nod].begin(); it != v[nod].end(); it++)
    {
        int nxt = *it;
        if (!viz[nxt])
        {
            dfs(nxt);
            if (dp[nxt] > 0)
                dp[nod] += dp[nxt];
        }

    }
    dp[nod] += val[nod];
    Smax = max(Smax, dp[nod]);
}

int main()
{
    fin >> n;
    for (int i = 1; i <= n; i++)
        fin >> val[i];
    for (int i = 1; i < n; i++)
    {
        int x, y;
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    fout << Smax << "\n";
    return 0;
}