#include<cstdio>

 #include<cstring>

 #include<vector>

 #include<algorithm>

 using namespace std;

 const int maxn = ;

 int dp[maxn][];//dp[i][0]表示第i个人不去，dp[i][1]表示第i个人去

 struct node{

     int f;//父节点

     vector<int>s;//子节点

 };

 node tree[maxn];

 int dfs(int cur){

     for(int i = ;i<tree[cur].s.size();i++){

         dfs(tree[cur].s[i]);

         dp[cur][] += dp[tree[cur].s[i]][];

         dp[cur][] += max(dp[tree[cur].s[i]][],dp[tree[cur].s[i]][]);

     }

 }

 int main(){

     int n;

     while(scanf("%d",&n)!=EOF){

         memset(dp,,sizeof(dp));

         for(int i = ;i<=n;i++)

             scanf("%d",&dp[i][]);

         int l,k;

         while(scanf("%d%d",&l,&k)&&(l||k)){

             tree[l].f = k;

             tree[k].s.push_back(l);

         }

         //寻找根节点

         int root = ;

         while(tree[root].f)

             root = tree[root].f;

         dfs(root);

         printf("%d\n",max(dp[root][],dp[root][]));

     }

     return ;

 }