#include <fstream>
#include <vector>
#include <climits>
#define DIM 16001
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
int n, sol, x, y, v[DIM], d[DIM];
bool viz[DIM];
vector<int> l[DIM];

void dfs(int nod) {
	viz[nod] = true;
	d[nod] = v[nod];
	for (int i = 0; i < l[nod].size(); i++) {
		int vec = l[nod][i];
		if (!viz[vec]) {
			dfs(vec);
			if (d[vec] > 0)
				d[nod] += d[vec];
		}
	}
	sol = max(sol, d[nod]);
}

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