#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

vector <int> a[16005];

int n,maxim=-100001,aux,v[16005];

bool calculat[16005];

void citire()
{
    int x,y;
    in>>n;
    for(int i=1;i<=n;i++)
    {
        in>>v[i];
    }
    for(int i=1;i<n;i++)
    {
        in>>x>>y;
        //cout<<x<<" "<<y<<'\n';
        a[x].push_back(y);
        a[y].push_back(x);
    }
}
int dfs(int nod)
{
    calculat[nod] = true;

    for(int i=0;i<a[nod].size();i++)
        if(!calculat[a[nod][i]])
        {
            aux=dfs(a[nod][i]);
            if(aux>0)
            {
                v[nod]+=aux;
            }
        }
    return v[nod];
}
int main()
{
    citire();

    maxim=dfs(1);
    for(int i=2;i<=n;i++)
        if(v[i]>maxim)
        {
            maxim=v[i];
        }

    out<<maxim<<"\n";
    return 0;
}