#include<cstdio>

#include<iostream>

#include<cstring>

using namespace std;

const int maxn = ;

int dp[maxn][]; // dp[i][state] 表示i节点 去/不去 分别的最大值

int father[maxn]; //记录每个节点父亲

int vis[maxn];

int N;

int root = ;

void dfs(int node){

    vis[node] = ;

    for(int i = ; i <= N; i++){

        if(vis[i] == - && father[i] == node){

            dfs(i);

            dp[node][] += dp[i][];//node去， 则i不能去

            dp[node][] += max(dp[i][], dp[i][]);// node不去， 比较一下两者最大值

        }

    }

}

int main() {

    while(cin >> N) {

        for(int i = ; i <= N; i++) cin >> dp[i][];

        for(int i = ; i <= N; i++){

            int u , v;

            cin >> v >> u;

            if(v ==  && u == ) break;

            root = u;

            father[v] = u;

        }

        memset(vis, -, sizeof(vis));

        dfs(root);

        cout << max(dp[root][], dp[root][]) << "\n";

    }

    return ;

}