#include <iostream>
#include <fstream>
#include <vector>
#include <stdint.h>
#include <limits.h>

const int32_t MAX_N = 16000;

int32_t vals[MAX_N];
std::vector<int32_t> adj[MAX_N];
int32_t max[MAX_N];

void DFS(int32_t node, int32_t prev) {
	int32_t maxSum = vals[node];
	for(int32_t next : adj[node]) {
		if(next == prev)
			continue;
		
		DFS(next, node);
		if(max[next] > 0)
			maxSum += max[next];
	}
	max[node] = maxSum;
}

int main() {
	std::ifstream fin("asmax.in");
	std::ofstream fout("asmax.out");

	int32_t n;
	fin >> n;
	for(int32_t i = 0; i != n; ++i)
		fin >> vals[i];
	for(int32_t i = 0; i != n - 1; ++i) {
		int32_t x, y;
		fin >> x >> y;
		--x; --y;
		adj[x].push_back(y);
		adj[y].push_back(x);
	}

	DFS(0, -1);

	int32_t maxSum = INT_MIN;
	for(int32_t i = 0; i != n; ++i) {
		if(max[i] > maxSum)
			maxSum = max[i];
	}

	fout << maxSum;

	fin.close();
	fout.close();

	return 0;
}