#include<fstream>
#include<iostream>
#include<climits>
#include<algorithm>
#include<cstring>
#include<cmath>
#include <vector>

#define MAX 100000

using namespace std;

ifstream f("asmax.in");
ofstream g("asmax.out");

//ifstream f("in.in");
//ofstream g("out.out");

vector <int> l[MAX+5];
int n,m,x,y;
int viz[MAX+5];
int val[MAX+5];
int s[MAX+5];
int sol=INT_MIN;

void dfs(int nod){

    s[nod]=val[nod];
    viz[nod] = 1;

    for(int i=0;i<l[nod].size();i++){
        int fiu = l[nod][i];
        if(viz[fiu] == 0){
            dfs(fiu);
            if(s[fiu]>0){
                s[nod]+=s[fiu];
            }
        }
    }

    sol = max(sol,s[nod]);

}

int main(){

    f>>n;
    for(int i=1;i<=n;i++){
        f>>val[i];
    }
    for(int i=1;i<n;i++){
        f>>x>>y;
        l[x].push_back(y);
        l[y].push_back(x);
    }

    dfs(1);

    g<<sol;

    f.close();
    g.close();
    return 0;
}