#include <bits/stdc++.h>
#define NMax 16001
#define inf -16000001

using namespace std;

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


int N;
vector <int> gr[NMax];
vector <int> v;             // valorile initiale ale nodurilor
vector <int> v_max;         // v_max[i] = valoarea maxima a subarborelui cu radacina in nodul i
bool viz[NMax];


void Read()
{
    fin >> N;

    v.resize(N+1);
    v_max.resize(N+1);

    for(int i = 1; i <= N; ++i)
        fin >> v[i];

    for(int i = 1; i < N; ++i)
    {
        int x, y;
        fin >> x >> y;
        gr[x].push_back(y);
        gr[y].push_back(x);
    }
}

void DFS(int s)
{
    viz[s] = 1;
    v_max[s] = v[s];

    for(auto i : gr[s])
    {
        if(!viz[i])
        {
            DFS(i);

            if(v_max[i] > 0)
                v_max[s] += v_max[i];
        }
    }
}

void Solve()
{
    int val_max = inf;
    for(int i = 1; i <= N; ++i)
        val_max = max(val_max, v_max[i]);
    fout << val_max;
}


int main()
{
    Read();
    DFS(1);             // conex, aciclic
    Solve();
    return 0;
}