#include <iostream>
#include <fstream>
#include <vector>

const int INF = 1<<30;
const int NMAX = 16e3 + 5;

using namespace std;

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

vector < int > g[NMAX];

int n;
int Max = -INF;
int v[NMAX];
bool viz[NMAX];

int dfs(int nod){
	viz[nod] = 1;
	int s = v[nod];
	for(int i : g[nod])
		if(!viz[i]){
			int x = dfs(i);
			if(x > 0)
				s += x;
		}
	Max = max(Max, s);
	return s;
}

int main(){
	fin >> n;
	for(int i = 1; i <= n; i++)
		fin >> v[i];
	for(int i = 1, x, y; i < n; i++){
		fin >> x >> y;
		g[x].push_back(y);
		g[y].push_back(x);
	}
	dfs(1);
	fout << Max;
	return 0;
}