#include <fstream>
#include <vector>
using namespace std;
ifstream cin("asmax.in");
ofstream cout("asmax.out");
const int NMAX=16e3+1;
vector<int>g[NMAX];
int v[NMAX],d[NMAX];
bool used[NMAX];
void dfs(int node)
{
    used[node]=true;
    d[node]=v[node];
    for(int i=0;i<g[node].size();i++)
    {
        int neighbour=g[node][i];
        if(used[neighbour]==false)
        {
            dfs(neighbour);
            if(d[neighbour]>0)
            {
                d[node]+=d[neighbour];
            }
        }
    }
}
int main()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>v[i];
    }
    for(int i=1;i<=n-1;i++)
    {
        int node1,node2;
        cin>>node1>>node2;
        g[node1].push_back(node2);
        g[node2].push_back(node1);
    }
    dfs(1);
    int max1=0;
    for(int i=1;i<=n;i++)
    {
        if(d[i]>max1)
            max1=d[i];
    }
    cout<<max1;
    return 0;
}