#include<cstdio>
#include<vector>
using namespace std;
const int N=1<<14;
bool f[N];
int n,sp[N],val[N];
vector<int> L[N];
void read()
{
	freopen("asmax.in","r",stdin);
	freopen("asmax.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
		scanf("%d",&val[i]);
	int x,y;
	for(int i=1;i<n;i++)
	{
		scanf("%d%d",&x,&y);
		L[x].push_back(y);
		L[y].push_back(x);
	}
}
void df(int nod)
{
	for(vector<int>::iterator it=L[nod].begin();it!=L[nod].end();it++)
		if(!f[*it])
		{
			f[*it]=true;
			df(*it);
			if(sp[*it]>=0)
				sp[nod]+=sp[*it];
		}
	sp[nod]+=val[nod];
}
void solve()
{
	int max=-(1<<30);
	for(int i=1;i<=n;i++)
		if(sp[i]>max)
			max=sp[i];
	printf("%d",max);
}
int main()
{
	read();
	f[1]=true;
	df(1);
	solve();
	return 0;
}