//ac

#include <iostream>

#include <cstdio>

#include <vector>

#include <deque>

#include <string>

#include <algorithm>

using namespace std;

#define inf 1000000000

int n, k, ret;

void f(int now, vector<vector<int> >& link, vector<int>& child, vector<int>& visited) {

visited[now] = 1;

for (int i = 0; i < link[now].size(); ++i) {

int next = link[now][i];

if (visited[next]) continue;

f(next, link, child, visited);

if (child[next] > 0) child[now] += child[next];

}

if (child[now] > ret) ret = child[now];

}

int main() {

scanf("%d", &n);

vector<vector<int> > link(n);

vector<int> child(n);

for (int i = 0; i < n; ++i) {

scanf("%d", &child[i]);

}

for (int i = 0; i < n - 1; ++i) {

int a, b;

scanf("%d %d", &a, &b);

--a, --b;

link[a].push_back(b);

link[b].push_back(a);

}

vector<int> visited(n, 0);

ret = -inf;

f(0, link, child, visited);

printf("%d\n", ret);

return 0;

}