#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <vector>
using namespace std;
int n;
int happy[6005];
vector<int> son[6005];
int dp[6005][3];
int vis[6005];
void dfs(int now)
{
    dp[now][1] = happy[now];
    dp[now][0] = 0;
    for(int i=0;i<son[now].size();i++)
    {
        int nex = son[now][i];
        dfs(nex);
        dp[now][1] += dp[nex][0];
        dp[now][0] += max(dp[nex][0],dp[nex][1]);
    }
}
int main()
{
    while(scanf("%d",&n)!=EOF&&n)
    {
        memset(dp,0,sizeof(dp));
        memset(vis,0,sizeof(vis));
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&happy[i]);
        }
        int l,k;
        while(1)
        {
            scanf("%d %d",&l,&k);
            if(l==0&&k==0) break;
            son[k].push_back(l);
            vis[l] = 1;
        }
        int father = 0;
        for(int i=1;i<=n;i++)
        {
            if(!vis[i])
            {
                father = i;
                break;
            }
        }
        dfs(father);
        printf("%d\n",max(dp[father][0],dp[father][1]));
        for(int i=1;i<=n;i++) son[i].clear();
    }
    return 0;
}