#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f ("asmax.in");
ofstream g ("asmax.out");
int n,rasp=-1000000;
bool viz[16001];
int suma_subarbore[16001];
int costuri[16001];
vector<int>adiacenta[16001];
void DFS(int nod)
{
    suma_subarbore[nod] = costuri[nod];
    for(int i = 0;i<adiacenta[nod].size();i++)
    {
        int vecin = adiacenta[nod][i];
        if(!viz[vecin])
        {
            viz[vecin]=1;
            DFS(vecin);
            if(suma_subarbore[vecin]>=0)
                suma_subarbore[nod]+=suma_subarbore[vecin];
        }
    }
}
int main()
{
    f >> n;
    for(int i = 1;i<=n;i++)
    {
        f >> costuri[i];
    }
    for(int i = 1;i<n;i++)
    {
        int x,y;
        f >> x >> y;
        adiacenta[x].push_back(y);
        adiacenta[y].push_back(x);
    }
    viz[1] = 1;
    DFS(1);
    for(int i = 1;i<=n;i++)
        rasp = max(rasp,suma_subarbore[i]);
    g << rasp;
}