#include <stdio.h>
#include <vector>
using namespace std;

const int N=17000;
int val[N],cost[N],smax=-1000000,n;
vector<int> a[N];
bool b[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);
		a[x].push_back(y);
		a[y].push_back(x);
	}
}

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

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

int main()
{
	
	freopen("asmax.in","r",stdin);
	freopen("asmax.out","w",stdout);
	citire();
	dfs(1);
	afisare();
	return 0;
}