#include <cstdio>
#include <iostream>
#include <set>
#include <climits>
#include <map>
#include <algorithm>
#include <list>
#include <vector>
#include <utility>
#include <cstdlib>

using namespace std;

int v[16005], dp[16005];
list<int> E[16005];

void dfs(int nod, int root) {
    dp[nod] = v[nod];
    for (list<int>::iterator it = E[nod].begin(); it != E[nod].end(); it++) {
        if (*it == root)
            continue;
        dfs(*it, nod);
        if (dp[*it] > 0)
            dp[nod] += dp[*it];
    }
}

int main() {
   // freopen("tt.txt", "r", stdin);
    freopen("asmax.in", "r", stdin);
    freopen("asmax.out", "w", stdout);

    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> v[i];
    }
    for (int i = 1; i < n; i++) {
        int a, b;
        cin >> a >> b;
        E[b].push_back(a);
        E[a].push_back(b);
    }
    dfs(1, 0);
    int ans = dp[1];
    for (int i = 1; i <= n; i++) {
        if (dp[i] > ans) ans = dp[i];
    }
    cout << ans;

    return 0;
}