#include <fstream>
#include <vector>
#include <algorithm>
#include <bitset>
#include <limits>
using namespace std;

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

const long long MaxV = numeric_limits<long long>::min();

vector<vector<int> > G;
vector<int> v;
long long S[16001];
bitset<16001> viz;
int n;

void Df(int node);
void Read();

int main()
{
	Read();
	Df(1);
	int r;
	r = *max_element(S + 1, S + n + 1);
	os << r;
	is.close();
	os.close();
	return 0;
}


void Df(int node)
{
	viz[node] = 1;
	S[node] = v[node];
	for ( const int& g : G[node] )
		if ( !viz[g] )
		{
			Df(g);
			S[node] += max(0LL, S[g]);
		}
}
			 
void Read()
{
	is >> n;
	G.resize(n + 1);
	v.resize(n + 1);
	for ( int i = 1; i <= n; ++i )
	{
		is >> v[i];
		S[i] = MaxV;
	}
	int x, y;
	for ( int i = 1; i < n; ++i )
	{
		is >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
}