#include<fstream>
#include<vector>
#include<bitset>
using namespace std;

const int NMAX = 16005;
int v[NMAX];
vector<int> g[NMAX];
bitset<NMAX>viz;

void dfs(int x)
{
	viz[x] = 1;
	for (vector<int>::iterator it = g[x].begin(); it != g[x].end(); it++)
	{
		if (!viz[*it])
		{
			dfs(*it);
			if (v[*it] > 0)
				v[x] += v[*it];
		}
	}
}



int main()
{
	ifstream fin("asmax.in");
	ofstream fout("asmax.out");
	int n;
	fin >> n;
	for (int i = 1; i <= n; i++)
	{
		fin >> v[i];
	}
	for (int i = 1; i <= n - 1; i++)
	{
		int x, y;
		fin >> x >> y;
		g[x].push_back(y);
		g[y].push_back(x);
	}
	dfs(1);
	int sol = v[1];
	for (int i = 1; i <= n; i++)
	{
		if (sol < v[i])
			sol = v[i];
	}
	fout << sol;
}