#include <iostream>
#include <fstream>
#include <algorithm>
#include <vector>
using namespace std;

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

#define N 16001

int n, val[N], viz[N], sum[N];
vector<int> a[N];

void dfs(int x){
    viz[x] = 1;
    sum[x] = val[x];

    for(int k : a[x]){
        if(viz[k] == 0){
            dfs(k);
            if(sum[k] > 0)
                sum[x] += sum[k];
        }
    }
}

int main(){
    in >> n;
    for(int i=1; i<=n; i++)
        in >> val[i];

    for(int i=1; i<=n-1; i++){
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    dfs(1);
    int maxim = -16000000;
    for(int i=1; i<=n; i++)
        maxim = max(maxim, sum[i]);
    out << maxim;
}