#include <fstream>
#include <vector>
using namespace std;

const int N=16001;
int v[N],sum[N],smax=-(1<<30),n;
vector<int> a[N];
int use[N];

ifstream in("asmax.in");
ofstream out("asmax.out");

void dfs(int x)
{
	if (use[x])
		return;
	use[x]=true;
	sum[x]=v[x];
	for (unsigned int i=0;i<a[x].size();i++)
	{
		int y=a[x][i];
		if (!use[y])
		{
			dfs(y);
			if (sum[y]>0)
				sum[x]+=sum[y];
		}
	}
	if (sum[x]>smax)
		smax=sum[x];
}

int main()
{
	int x,y,i;
	in>>n;
	for (i=1;i<=n;i++)
		in>>v[i];
	for (i=1;i<=n-1;i++)
	{
		in>>x>>y;
		a[x].push_back(y);
		a[y].push_back(x);
	}
	dfs(1);
	out<<smax<<"\n";
	return 0;
}