// Include
#include <fstream>
#include <vector>
using namespace std;

// Definitii
#define pb push_back

// Constante
const int sz = (int)16e3+1;
const int oo = (1<<30)-1;

// Functii
int dfs(int node, int father);

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

int nodes;
int values[sz];
int maxSum = -oo;

vector<int> graph[sz];

// Main
int main()
{
	in >> nodes;
	for(int i=1 ; i<=nodes ; ++i)
		in >> values[i];
	
	int rFrom, rTo;
	for(int i=1 ; i<nodes ; ++i)
	{
		in >> rFrom >> rTo;
		graph[rFrom].pb(rTo);
		graph[rTo].pb(rFrom);
	}
	
	dfs(1, -1);
	out << maxSum << '\n';
	
	in.close();
	out.close();
	return 0;
}

int dfs(int node, int father)
{
	int sum = values[node];
	vector<int>::iterator it, end=graph[node].end();
	for(it=graph[node].begin() ; it!=end ; ++it)
	{
		if(*it == father)
			continue;
		int tempSum = dfs(*it, node);
		if(tempSum > 0)
			sum += tempSum;
	}
	maxSum = max(maxSum, sum);
	return sum;
}