//nu ii frumos sa te uiti pe sursele altora:))...hotule....nu o sti face singur?:))
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");

#define MAX 16020

vector <int> G[MAX];
int ssm[MAX];
int a[MAX], viz[MAX];

void dfs(int nod)
{
    viz[nod]=1;
    int k=0;
    for(int i=0;i<G[nod].size();i++)
    {
        if(!viz[G[nod][i]])
        {
            dfs(G[nod][i]);
            if(ssm[G[nod][i]]>0)
                k+=ssm[G[nod][i]];
        }
    }
    ssm[nod]=k+a[nod];
}

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