1 //#pragma comment(linker,"/STACK:102400000,102400000")
 2 #include <map>
 3 #include <set>
 4 #include <stack>
 5 #include <queue>
 6 #include <cmath>
 7 #include <ctime>
 8 #include <vector>
 9 #include <cstdio>
10 #include <cctype>
11 #include <cstring>
12 #include <cstdlib>
13 #include <iostream>
14 #include <algorithm>
15 using namespace std;
16 #define INF 1e9
17 #define inf (-((LL)1<<40))
18 #define lson k<<1, L, mid
19 #define rson k<<1|1, mid+1, R
20 #define mem0(a) memset(a,0,sizeof(a))
21 #define mem1(a) memset(a,-1,sizeof(a))
22 #define mem(a, b) memset(a, b, sizeof(a))
23 #define FOPENIN(IN) freopen(IN, "r", stdin)
24 #define FOPENOUT(OUT) freopen(OUT, "w", stdout)
25 template<class T> T CMP_MIN(T a, T b) { return a < b; }
26 template<class T> T CMP_MAX(T a, T b) { return a > b; }
27 template<class T> T MAX(T a, T b) { return a > b ? a : b; }
28 template<class T> T MIN(T a, T b) { return a < b ? a : b; }
29 template<class T> T GCD(T a, T b) { return b ? GCD(b, a%b) : a; }
30 template<class T> T LCM(T a, T b) { return a / GCD(a,b) * b;    }
31
32 //typedef __int64 LL;
33 //typedef long long LL;
34 const int MAXN = 6010;
35 const int MAXM = 100005;
36 const double eps = 1e-13;
37 //const LL MOD = 1000000007;
38
39 int N, a[MAXN], dp[MAXN][2];
40 int fa[MAXN];
41 vector<int>e[MAXN];
42
43 void DFS(int u)
44 {
45     int s0 = 0, s1 = 0;
46     for(int i=0;i<e[u].size();i++)
47     {
48         DFS(e[u][i]);
49         s0 += MAX( dp[e[u][i]][0], dp[e[u][i]][1] );
50         s1 += dp[e[u][i]][0];
51     }
52     dp[u][0] = s0;
53     dp[u][1] = s1 + a[u];
54 }
55
56 int main()
57 {
58     //FOPENIN("in.txt");
59     while(~scanf("%d", &N))
60     {
61         mem0(dp);
62         for(int i=1;i<=N;i++)
63         {
64             scanf("%d", &a[i]);
65             fa[i] = i;
66             e[i].clear();
67         }
68         int x, y;
69         while(scanf("%d %d", &x, &y) && (x||y) ){
70             e[y].push_back(x);
71             fa[x] = y;
72         }
73         int ans = 0;
74         for(int i=1;i<=N;i++) if(fa[i] == i)
75         {
76             DFS(i);
77             ans += MAX(dp[i][0], dp[i][1]);
78         }
79         printf("%d\n", ans);
80     }
81     return 0;
82 }