#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 16000;

int n; 

int cost[NMAX + 1];

int best[NMAX + 1]; //best[i] = cel mai bun cost care se poate forma cu un subarbore cu radacina in i, care il cuprinde pe i
					//considerand ca radacina este in nodul 1

vector<int> g[NMAX + 1];

int smax;

 bool in[NMAX + 1]; int rad;

void read() {

	fin >> n; 

	for(int i = 1; i <= n ; ++i)
		fin >> cost[i];

	for(int i = 1; i < n ; ++i) {

		int x; int y;
		fin >> x >> y;

		g[x].push_back(y);

		in[y] = true;
	}
}

void dfs(int node) {

	for(int x : g[node])
			dfs(x);

	best[node] = cost[node];

	for(int x : g[node])
		if(best[x] > 0)
			best[node] += best[x];

	if(best[node] > smax) smax = best[node];

}

void solve() {

	for(int i = 1; i <= n; ++i)
		if(in[i] == false) {
			rad = i; break;
		}
	

	dfs(rad);

	fout << smax << '\n'; 

}

int main() {

	read();

	solve();

	return 0;
}