#include<cstdio>
#include<vector>
#include<cstring>
#define si short int
#define nmax 16005
using namespace std;
si v[nmax],n;
vector<short int> G[nmax];
bool use[nmax];
int DFS(int nod)
{
	int s=0,val;
	use[nod]=1;
	for(unsigned si i=0;i<G[nod].size();i++)
		if(!use[G[nod][i]])
		{
			val=DFS(G[nod][i]);
			if(val<=0)
				continue;
			s+=val;
		}
	s+=v[nod];
	return s;
}
void read()
{
	si i,x,y;
	freopen("asmax.in","r",stdin);
	scanf("%d",&n);
	for(i=1;i<=n;i++)
		scanf("%d",&v[i]);
	for(i=0;i<n-1;i++)
	{
		scanf("%d %d",&x,&y);
		G[x].push_back(y);
		G[y].push_back(x);
	}
}
int main()
{
	int i,val,max;
	read();
	max=DFS(1);
	for(i=2;i<=n;i++)
	{
		memset(use,0,sizeof(use));
		val=DFS(i);
		if(val>max)
			max=val;
	}
	freopen("asmax.out","w",stdout);
	printf("%d\n",max);
	return 0;
}