#include <bits/stdc++.h>

using namespace std;

ifstream f("asmax.in");
ofstream g("asmax.out");

set <int > v[16001];
int lim[16001],n, scor[16001];
vector <int > val;

void citire()
{
    f >> n;
    val.push_back(0);
    for(int i = 1;i <= n;i ++)
        {
            int x;
            f >> x;
            val.push_back(x);
        }
        
    for(int i = 1;i < n;i ++)
    {
        int x, y;
        f >> x >> y;
        v[x].insert(y);
        v[y].insert(x);
    }
    
    
}

void dfs(int nod)
{
    lim[nod] = 1;
    scor[nod] = val[nod];
    for(auto i : v[nod])
    {
        if(!lim[i])
            dfs(i);
        if(scor[i] > 0)
            scor[nod] += val[i]; 
    }
}
void rez()
{
    dfs(n);
    
    g << *max_element(scor + 1, scor + 1 + n);
    
}
int main()
{
    citire();
    rez();
    return 0;
}