#include <vector>
#include <fstream>
 
using namespace std;
 
ifstream fin ("asmax.in");
ofstream fout ("asmax.out");
 
const int Dim = 16001;
using VI = vector < int >;
using VVI = vector < VI >;
 
VVI G;
int n,A[Dim],ma = -0x3f3f3f3f;
bool V[Dim];
int Dfs(int node);
 
int main() {
 
	fin >> n;
	G = VVI(n+1);
	for ( int i = 1; i <= n; ++i)
		fin >> A[i];
	int x,y;
	for ( int i = 1; i < n; ++i) {
		fin >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
		}
	Dfs(1);
	fout << ma;
}
 
int Dfs(int node) {
 
	V[node] = true;
	int sum = A[node];
	for ( const int & i : G[node] )
		if(!V[i] )
			sum = max(sum,Dfs(i) + sum);
	ma = max(ma, sum);
	return sum;
}