#include<fstream>
#include<algorithm>
using namespace std;
struct nod{int info,c;nod*adr;}*v[16003],*p;
int n,i,x,y,val[16003];
short viz[16003];
int smax[16003],maxx;
void dfs(int nd)
{int cost=0;
	viz[nd]=1;
	nod*p=v[nd];
	while(p)
	{
		if(!viz[p->info])
		{
		 dfs(p->info);
		 if(smax[p->info]>0)
		  cost+=smax[p->info];
		}
		p=p->adr;
	}
  smax[nd]=cost+val[nd];
  maxx=max(maxx,smax[nd]);
}
int main()
{
	ifstream f("asmax.in");ofstream g("asmax.out");
	f>>n;
	for(i=1;i<=n;i++)f>>val[i];
	for(i=1;i<n;i++)
	{
		f>>x>>y;
		p=new nod;
		p->info=y; p->adr=v[x]; v[x]=p;
		p=new nod;
		p->info=x; p->adr=v[y]; v[y]=p;
	}
	dfs(1);
	g<<maxx<<'\n';
return 0;}