#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
#define MAX 16005
vector < int > G[MAX];
int viz[MAX],sm[MAX],a[MAX];
void dfs(int nod)
{
    int k=0;
    viz[nod]=1;
    for (int i = 0; i<G[nod].size(); i++){
        if(!viz[G[nod][i]]) {
                dfs(G[nod][i]);
                    if(sm[G[nod][i]]>0)
                        k+=sm[G[nod][i]];
            }
    }
    sm[nod]=a[nod]+k;
}

int main()
{
    int n,x,y;
    fin >> n;
    for (int i = 1; i<=n; i++)
        fin >> a[i];
    for (int i = 1; i<n; i++) {
            fin >> x >> y;
            G[x].push_back(y);
            G[y].push_back(x);
    }
    dfs(1);
    int mx=1;
    for (int i = 1; i<=n; i++)
        if(sm[mx]<sm[i])
            mx=i;
    fout << sm[mx] << "\n";
    return 0;
}