#include<cstdio>
#include<algorithm>
using namespace std;
#define maxn 6010int fa[maxn],dp[maxn][2];
int root,n;
int v[maxn];
int nxt[maxn],head[maxn];void treedp(int x){for(int i = head[x];i;i = nxt[i]){treedp(i);dp[x][0] += max(dp[i][1],dp[i][0]);//dp[x][0]代表上司x不来时的最大快乐指数dp[x][1] += dp[i][0];//dp[x][1]代表上司来的
    }
}int main() {scanf("%d",&n);for(int i = 1; i <= n; i++)scanf("%d",&dp[i][1]);for(int i = 1; i < n; i++) {int x,y;scanf("%d%d",&x,&y);v[x] ++;//记录一下有没有上司nxt[x] = head[y];head[y] = x;//对，像链式前向星的东西（我还理解了好久【划掉
    }for(int i = 1; i <= n; i++)if(!v[i]) {//没有上司的就是最大上司啦root = i;break;}treedp(root);//从树根开始dpprintf("%d",max(dp[root][0],dp[root][1]));//取最高上司来和不来的最大快乐指数return 0;
}

#include<cstdio>
#include<algorithm>
using namespace std;
#define maxn 16010int dp[maxn];
int cnt,head[maxn * 2];
int f[maxn];//记录当前子节点到之下的花的最大值
int ans = -2147483647;//因为可能全是负的所以ans搞到最小struct EDGE{int nxt,to;
}edge[maxn * 2];void add(int x,int y){edge[++cnt].to = y;edge[cnt].nxt = head[x];head[x] = cnt;
}//正常的加边看上去真舒服啊void treedp(int u,int fa){f[u] = dp[u];//给f[u]赋值为它本身的大小for(int i = head[u];i;i = edge[i].nxt){int v = edge[i].to;//v是u的儿子if(v != fa){//唔防止双向加边跑回去
      treedp(v,u);f[u] += max(0,f[v]);}}ans = max(ans,f[u]);//反正所有的花都在一根上不需要加和什么的（我在说什么废话
}int main(){int n;scanf("%d",&n);for(int i = 1;i <= n;i++)scanf("%d",&dp[i]);for(int i = 1;i < n;i++){int x,y;scanf("%d%d",&x,&y);add(x,y);add(y,x);}treedp(1,0);//将1的父节点定义为0printf("%d",ans);return 0;
}

#include<cstdio>
#include<algorithm>
using namespace std;
#define maxn 1510struct EDGE{int nxt,to;
}edge[maxn];int cnt,head[maxn];
int v[maxn];
int dp[maxn][2];void add(int x,int y){edge[++cnt].to = y;edge[cnt].nxt = head[x];head[x] = cnt;
}void treedp(int x){dp[x][1] = 1;//放的地方都是一for(int i = head[x];i;i = edge[i].nxt){int u = edge[i].to;treedp(u);dp[x][0] += dp[u][1];//当前点不放，下一个点一定要放dp[x][1] += min(dp[u][1],dp[u][0]);当前放了下一个点不一定放不放}
}int main(){int n;scanf("%d",&n);for(int i = 0;i < n;i++){int r,k;scanf("%d%d",&r,&k);for(int j = 0;j < k;j++){int p;scanf("%d",&p);v[p]++;add(r,p);}}int root;for(int i = 0;i < n;i++)if(!v[i]){root = i;break;}//唔又是找根
  treedp(root);printf("%d",min(dp[root][0],dp[root][1]));return 0;
}