#include <fstream>
#include <vector>
#define input "asmax.in"
#define output "asmax.out"
using namespace std;

const int N=16001;
const int s=1;
int val[N],cost[N],smax=-(1<<30),n;
vector<int> g[N];
bool iw[N];


void citire()
{
	int x,y,i;
	scanf("%d",&n);
	for (i=1;i<=n;i++)
		scanf("%d",&val[i]);
	for (i=1;i<=n-1;i++)
	{
		scanf("%d%d",&x,&y);
		g[x].push_back(y);
		g[y].push_back(x);
	}
}

void dfs(int x)
{
	if (iw[x])
		return;
	iw[x]=true;
	cost[x]=val[x];
	for (int i=0;i<g[x].size();i++)
	{
		int y=g[x][i];
		if (!iw[y])
		{
			df(y);
			if (cost[y]>0)
				cost[x]+=cost[y];
		}
	}
	if (cost[x]>smax)
		smax=cost[x];
}

void afisare()
{
	printf("%d",smax);
}

int main()
{
	
	freopen(input,"r",stdin);
	freopen(output,"w",stdout);
	citire();
	dfs(s);
	afisare();
	return 0;
}