#include <bits/stdc++.h>
#define ll long long
#define MAXN 16001

using namespace std;

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

vector<int> edges[MAXN];
int val[MAXN], sum[MAXN];
int max_sum = INT_MIN;
bitset<MAXN> visited;

void dfs(int start) {
    visited[start] = 1;
    sum[start] = val[start];
    for(int i = 0; i < edges[start].size(); i++) {
        if(!visited[edges[start][i]]) {
            dfs(edges[start][i]);
            if(sum[edges[start][i]] > 0)
                sum[start] += sum[edges[start][i]];
        }
    }
    max_sum = max(max_sum, sum[start]);
}

int main() {
    int n;
    fin >> n;

    for(int i = 1; i <= n; i++)
        fin >> val[i];
    for(int i = 1; i < n; i++) {
        int x, y;
        fin >> x >> y;
        edges[x].push_back(y);
        edges[y].push_back(x);
    }

    dfs(1);
    fout << max_sum;
    return 0;
}