#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f("asmax.in");
ofstream g ("asmax.out");
vector<int>adiacenta[16001];
int n;
bool viz[16001];
int valori[16001],sume[16001];
void DFS(int nod)
{
    viz[nod] = 1;
    sume[nod] = valori[nod];
    for(auto &x:adiacenta[nod])
    {
        if(!viz[x])
        {
            DFS(x);
            if(sume[x]>0)
            {
                sume[nod]+=sume[x];
            }
        }
    }
}
int main()
{
    f >> n;
    for(int i = 1; i<=n; i++)
        f >> valori[i];
    for(int i = 1; i<n; i++)
    {
        int x,y;
        f >> x >> y;
        adiacenta[x].push_back(y);
        adiacenta[y].push_back(x);
    }
    DFS(1);
    int s = -10000000;
    for(int i = 1; i<=n; i++)
        s = max(s,sume[i]);
    g << s;

}