#include <bits/stdc++.h>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
vector<int> valori, dist;
vector<vector<int> > graph;
vector<bool> vizitat;
int n;
void asmax(int nod){
    vizitat[nod]=1;
    int max1=0;
    for(auto it:graph[nod]){
        if(vizitat[it]==0){
            asmax(it);
            max1+=max(0, valori[it]);
        }
    }
    valori[nod]+=max1;
}
int main(){
    fin>>n;
    valori.resize(n+1);
    graph.resize(n+1,vector<int>());
    vizitat.resize(n+1);
    dist.resize(n+1);
    for(int i=1;i<=n;i++){
        fin>>valori[i];
    }
    for(int i=1;i<=n-1;i++){
        int x, y;
        fin>>x>>y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    asmax(1);
    fout<<*max_element(valori.begin()+1,valori.end());


}