#include <iostream>
#include <fstream>
#include <vector>
#define NN 160001
using namespace std;

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

vector <int> adiacenta[NN];

bool visited[NN];

int cost[NN];

int maxim = -10000;


void DFS(int vf)
{
	visited[vf] = true;
	
	for(int i = 0; i < adiacenta[vf].size(); ++i)
	{
	    if (!visited[adiacenta[vf][i]])
		{
		    DFS(adiacenta[vf][i]);
	    	if (cost[adiacenta[vf][i]] >= 0) cost[vf] += cost[adiacenta[vf][i]];
		}
	}
    
}

int main()
{
    int N, a, b, s;
    in>>N;
    
    for(int i = 1; i <= N; ++i)
        in>>cost[i];
        
    for(int i = 1; i <= N; ++i)
        visited[i] = false;
    
    for(int i = 1; i < N; ++i)
    {
        in>>a>>b;
        adiacenta[a].push_back(b);
        adiacenta[b].push_back(a);
    }
  
    DFS(1);
    
    for(int i = 1; i <= N; ++i)
    {
        if(cost[i] > maxim)
        {
            maxim = cost[i];
        }
    }
    
    out<<maxim;
    
    return 0;
}