#include <iostream>
#include <vector>
#include <fstream>
#include <climits>
#define MAX 16002
using namespace std;
int sum,val[MAX],vf[MAX],maxi = INT_MIN,ans,x,y,n,d[MAX];
vector<int> v[MAX];

ifstream fin("asmax.in");
ofstream fout("asmax.out");

void dfs(int nod){
    vf[nod] = 1;
    d[nod] = val[nod];
    for(int i = 0; i < v[nod].size(); i++){
        int vecin = v[nod][i];
        if(vf[vecin] == 0){
            dfs(vecin);
            if(d[vecin] > 0){
                d[nod] += d[vecin];
            }
        }
    }
    maxi = max(maxi, d[nod]);
}

int main()
{
    fin >> n;
    for(int i = 1; i <= n; i++){
        fin >> val[i];
    }
    for(int i = 1; i < n; i++){
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    fout << maxi;
    return 0;
}