#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<algorithm>
#include<iostream>
#include<queue>
#include<map>
#include<cmath>
#include<set>
#include<stack>
#define ll long long
#define pb push_back
#define max(x,y) ((x)>(y)?(x):(y))
#define min(x,y) ((x)>(y)?(y):(x))
#define cls(name,x) memset(name,x,sizeof(name))
using namespace std;
const int inf=1e9+10;
const ll llinf=1e16+10;
const int maxn=6e3+10;
const int maxm=1e2+10;
const int mod=1e9+7;
int n;
vector<int> v[maxn];
int dp[maxn][2];
int val[maxn];
int pre[maxn];
void solve(int rt)
{
    dp[rt][1]=val[rt];
    dp[rt][0]=0;
    for(int i=0;i<v[rt].size();i++)
    {
        int to=v[rt][i];
        solve(to);
        dp[rt][1]+=dp[to][0];
        dp[rt][0]+=max(dp[to][0],dp[to][1]);
    }
}
int main()
{
    //freopen("in.txt","r",stdin);
    while(~scanf("%d",&n))
    {
        for(int i=1;i<=n;i++)
            scanf("%d",&val[i]);
        for(int i=1;i<=n;i++)
            pre[i]=-1;
        int a,b;
        for(int i=1;i<=n;i++)
            v[i].clear();
        while(~scanf("%d %d",&a,&b)&&a!=0&&b!=0)
        {
            v[b].pb(a);
            pre[a]=b;
        }
        int rt=1;
        while(pre[rt]!=-1)
            rt=pre[rt];
        solve(rt);
        printf("%d\n",max(dp[rt][0],dp[rt][1]));
    }
    return 0;
}