#include<map>
#include<set>
#include<cmath>
#include<queue>
#include<stack>
#include<vector>
#include<cstdio>
#include<cassert>
#include<iomanip>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
#define pi acos(-1)
#define ll long long
#define mod 1000000007
#define ls l,m,rt<<1
#define rs m+1,r,rt<<1|1
#pragma comment(linker, "/STACK:1024000000,1024000000")

using namespace std;

const double g=10.0,eps=1e-9;
const int N=6000+10,maxn=5000+10,inf=0x3f3f3f3f;

vector<int>v[N];
int dp[N][2],father[N];
void tree_dp(int x)
{
    for(int i=0;i<v[x].size();i++)
    {
        int y=v[x][i];
        tree_dp(y);
        dp[x][1]+=dp[y][0];
        dp[x][0]+=max(dp[y][0],dp[y][1]);
    }
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    while(cin>>n){
        for(int i=1;i<=n;i++)
        {
            cin>>dp[i][1];
            v[i].clear();
            father[i]=i;
            dp[i][0]=0;
        }
        int a,b;
        while(cin>>a>>b,a&&b){
            v[b].push_back(a);
            father[a]=b;
        }
        int root=1;
        while(root!=father[root])root=father[root];
        tree_dp(root);
        cout<<max(dp[root][1],dp[root][0])<<endl;
    }
    return 0;
}