#include <bits/stdc++.h>
using namespace std;
ifstream fi("asmax.in");
ofstream fo("asmax.out");

const int NMAX = 16005;

int n;
int val[NMAX];
bool viz[NMAX];
int dp[NMAX];
vector <int> G[NMAX];

void dfs(int nod) {
    viz[nod] = 1;
    dp[nod] = val[nod];

    for (auto x: G[nod])
        if (!viz[x]) {
            dfs(x);
            if (dp[x] > 0)
                dp[nod] += dp[x];
        }
}

int main()
{
    fi >> n;
    for (int i = 1; i <= n; i++) {
        fi >> val[i];
    }

    for (int i = 1; i < n; i++) {
        int u, v;
        fi >> u >> v;
        G[u].push_back(v);
        G[v].push_back(u);
    }

    dfs(1);

    int ans = -1005;
    for (int i = 1; i <= n; i++)
        ans = max(ans, dp[i]);

    fo << ans;


    return 0;
}