#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<queue>
#include<stack>
#include<map>
#include<vector>
#include<set>
#include<bitset>
using namespace std;
#define PI acos(-1.0)
#define eps 1e-8
typedef long long ll;
typedef pair<int,int> P;
const int N=1e5+100,M=1e5+100;
const int inf=0x3f3f3f3f;
const ll INF=1e18+7,mod=1e9+7;
struct edge
{
    int from,to;
    int next;
};
edge es[M];
int cnt,head[N];
int in[N];
int dp[N][2];
void init()
{
    cnt=0;
    memset(head,-1,sizeof(head));
    memset(in,0,sizeof(in));
    memset(dp,0,sizeof(dp));
}
void addedge(int u,int v)
{
    cnt++;
    es[cnt].from=u,es[cnt].to=v;
    es[cnt].next=head[u];
    head[u]=cnt;
}
void dfs(int u)
{
    for(int i=head[u]; i!=-1; i=es[i].next)
    {
        int v=es[i].to;
        dfs(v);
        dp[u][1]+=dp[v][0];
        dp[u][0]+=max(dp[v][1],dp[v][0]);
    }
    ///cout<<u<<" * "<<dp[u][0]<<" * "<<dp[u][1]<<endl;
}
int main()
{
    int n;
    while(~scanf("%d",&n))
    {
        init();
        for(int i=1; i<=n; i++) scanf("%d",&dp[i][1]);
        int u,v;
        while(scanf("%d%d",&u,&v)&&!(u==0&&v==0))
        {
            addedge(v,u);
            in[u]++;
        }
        int root;
        for(int i=1; i<=n; i++)
            if(!in[i]) root=i;
        dfs(root);
        printf("%d\n",max(dp[root][0],dp[root][1]));
    }
    return 0;
}