#include<bits/stdc++.h>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
#define INF 100000

vector<int>v[16001];
int n,a[16001],summax,viz[16001],ans=-INF;

void dfs(int nod)
{
    viz[nod]=1;
    int i;
    for(i=0;i<v[nod].size();i++)
        if(viz[v[nod][i]]==0)
             {
                 dfs(v[nod][i]);
                 if(a[v[nod][i]]>0)
                 a[nod]+=a[v[nod][i]];
             }
    ans=max(ans,a[nod]);
}

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