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

int main() {
    ifstream fin("asmax.in");
    ofstream fout("asmax.out");
    int n;
    fin >> n;

    vector<long long> dp(n + 1);
    vector<long long> in_degree(n + 1);
    for (int i = 1; i <= n; ++i) {
        fin >> dp[i];
    }

    vector<vector<int>> adj(n + 1);
    for (int i = 1, x, y; i < n; ++i) {
        fin >> x >> y;
        adj[x].push_back(y);
        // adj[y].push_back(x);
        ++in_degree[y];
        // ++in_degree[x];
    }

    long long sol = LONG_MIN;
    function<void(int)> dfs = [&](int nod) -> void {
        for (int vec : adj[nod]) {
            --in_degree[vec];
            if (!in_degree[vec]) {
                dfs(vec);
                dp[nod] = max(dp[nod], dp[nod] + dp[vec]);
            }
        }
        sol = max(sol, dp[nod]);
    };
    
    for (int i = 1; i <= n; ++i) {
        if (!in_degree[i]) {
            dfs(i);
        }
    }

    fout << sol << '\n';
    return 0;
}