MLE???

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define int long long
const int N = 16010;
int f[N];
vector<int>g[N];
int ans = -1;
int n;
int a[N]; 
inline void dfs(int fa){
	f[fa] = a[fa];
	for(auto son:g[fa]){
		if(son == fa)continue;
		dfs(son);
		if(f[son] >= 1){
			f[fa] += f[son];
		}
	}
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin >> n;
	for(int i = 1;i <= n;i ++){
		cin >> a[i];
	}
	for(int i = 1;i < n;i ++){
		int u,v;
		cin >> u >> v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	dfs(1);
	for(int i = 1;i <= n;i ++){
		ans = max(ans,f[i]);
	}
	cout << ans;
	return 0;
}