#include <bits/stdc++.h>
#include <fstream>
#include <vector>
#include <bitset>
#include <unordered_map>
#include <algorithm>
#include <queue>
#include <math.h>
#include <iomanip>
#include <stack>
#include <string.h>
#include <set>
 
using namespace std;
 
typedef long long ll;
 
ifstream in("asmax.in");
ofstream out("asmax.out");

const int DIM = 16007;

vector <int> v[DIM];
int w[DIM];

void dfs(int nod = 1, int father = 0)
{
	for(auto i : v[nod])
		if(i != father)
		{
			dfs(i, nod);
			
			if(w[i] > 0)
				w[nod] += w[i];
		}
}

int main()
{
	int n;
	in >> n;
	
	for(int i = 1; i <= n; i++)
		in >> w[i];
	
	for(int i = 1; i < n; i++)
	{
		int x, y;
		in >> x >> y;
		
		v[x].push_back(y);
		v[y].push_back(x);
	}
	
	dfs();
	
	int max_sum = 0;
	
	for(int i = 1; i <= n; i++)
		max_sum = max(max_sum, w[i]);
	
	out << max_sum;
}