#include <bits/stdc++.h>
#define Nmax 16005
using namespace std;

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

int N, ans;
int dp[Nmax], v[Nmax];
vector<int> G[Nmax];

void DFS(int node, int father) {
    dp[node] = v[node];
    for (auto it: G[node]) {
        if (it == father) continue;
        DFS(it, node);
        if (dp[it] > 0) dp[node] += dp[it];
    }
      ans = max(ans, dp[node]);
}
int main()
{
    fin >> N;
    for (int i = 1; i <= N; ++i)
        fin >> v[i];
    for (int i = 1; i < N; ++i) {
        int x, y;
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }

    ans = -1e9;
    DFS(1, 0);

    fout << ans << '\n';

    return 0;
}