#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <iterator>
#include <climits>
using namespace std;

ifstream f("asmax.in");
ofstream g("asmax.out");
int node[16001],n,sum[16001],Max=INT_MIN;
bool visited[16001];
vector <int> adj[16001];

void Solve(int root,int parent)
{

    sum[root]=node[root];
    visited[root]=1;
    for(vector<int>::iterator it=adj[root].begin();it!=adj[root].end();it++)
    {
        if(visited[*it]==0)
        {
            visited[*it]=1;
            Solve(*it,root);
        }
    }

    for(vector<int>::iterator it=adj[root].begin();it!=adj[root].end();it++)
    {
        if(*it!=parent)
        {

            if(sum[*it]>0)
            {
                sum[root]+=sum[*it];
            }
        }
    }
    Max=max(Max,sum[root]);

}

int main()
{
    f>> n;
    for(int i=1;i<=n;i++)
        f >> node[i];

    int x,y;
    for(int i=1;i<n;i++)
    {
        f >> x >> y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    Solve(1,0);

    g << Max << "\n";

    return 0;
}