#include<bits/stdc++.h>
#define pb push_back
using namespace std;
 
ifstream fin("asmax.in");
ofstream fout("asmax.out");

int eFiu[16005], verify[16005], n, x, y;
vector <int> fiu[16005], tata[16005];  
long long val[16005], best = -1e9; 

void bestSum(int copil) {
	verify[copil] = 1;
	for (auto next  : fiu[copil]) 
		if(verify[next] == 0)
			bestSum(next);
	best = max(val[copil], best);  
	for(auto tatal : tata[copil])
	val[tatal] = max(val[tatal], val[tatal] + 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;
		tata[y].pb(x);
		fiu[x].pb(y);
		eFiu[y] = 1;
	}	
	for (int i = 1; i <= n; i++) 
		if (eFiu[i] == 0) 
			bestSum(i);	
	fout << best;
}