1 #include <cstdio>
 2 #include <cstring>
 3 #include <cstdlib>
 4 #include <queue>
 5 #include <stack>
 6 #include <vector>
 7 #include <iostream>
 8 #include "algorithm"
 9 using namespace std;
10 typedef long long LL;
11 const int MAX=6005;
12 int n,root;
13 int a[MAX];
14 int tot;
15 int head[MAX],adj[MAX],next[MAX];
16 int f[MAX][2];
17 void addedge(int u,int v){
18     tot++;
19     adj[tot]=v;
20     next[tot]=head[u];
21     head[u]=tot;
22 }
23 void init(){
24     int i,j;
25     int u,v;
26     int t[MAX];
27     memset(t,0,sizeof(t)); 
28     scanf("%d",&n);
29     for (i=1;i<=n;i++)
30      scanf("%d",a+i);
31     for (i=1;i<n;i++)
32     {scanf("%d%d",&v,&u);
33      addedge(u,v);
34      t[v]++;
35     }
36     for (i=1;i<=n;i++)
37      if (t[i]==0)
38      {root=i;
39       break;
40      }
41     memset(f,-1,sizeof(f));
42 }
43 int dfs(int x,int k){
44     int i,j;
45     if (f[x][k]!=-1)
46      return f[x][k];
47     if (k==1)
48     {int y=0;
49      for (i=head[x];i;i=next[i])
50       y+=dfs(adj[i],0);
51      f[x][k]=a[x]+y;
52     }
53     else
54     {int y=0;
55      for (i=head[x];i;i=next[i])
56       y+=max(dfs(adj[i],0),dfs(adj[i],1));
57      f[x][k]=y;
58     }
59     return f[x][k];
60 }
61 int main(){
62     freopen ("party.in","r",stdin);
63     freopen ("party.out","w",stdout);
64     init();
65     printf("%d",max(dfs(root,0),dfs(root,1)));
66     return 0;
67 }