#include<bits/stdc++.h>
#define pb push_back
using namespace std;
 
ifstream fin("asmax.in");
ofstream fout("asmax.out");
 
int  tata[16005], val[16005], n, x, y, best = -1e5, radacina;
vector <int> fiu[16005];
 
void bestSum(int copil) {
	for (auto next  : fiu[copil]) 
		bestSum(next);
	best = max(val[copil], best);  
	val[tata[copil]] = max(val[tata[copil]], val[tata[copil]] + val[copil]);
}
 
int main() {
	fin >> n;	
	for (int i = 1; i <= n; i++)
		fin >> val[i];
	for (int i = 1; i < n; i++) {
		fin >> x >> y;
		if(!radacina)
			radacina = x;
		tata[y] = x;
		fiu[x].pb(y);
	}	
	bestSum(radacina);

	fout << best;
}