#include <bits/stdc++.h>
#define dim 16005
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
int sum[dim],n;
vector <int> graph[dim];
void Read()
{
    f>>n;
    for(int i=1;i<=n;++i)
        f>>sum[i];
    for(int i=1;i<n;++i)
    {
        int x,y;
        f>>x>>y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
}
void Dfs(int node=1,int daddy=0)
{
    for(int i=0;i<graph[node].size();++i)
    {
        int son=graph[node][i];
        if(son!=daddy)
        {
            Dfs(son,node);
            if(sum[son]>=0)
                sum[node]+=sum[son];
        }
    }
}
void Solve()
{
    int ans=sum[1];
    for(int i=2;i<=n;++i)
        ans=max(ans,sum[i]);
    g<<ans;
}
int main()
{
    Read();
    Dfs();
    Solve();
    return 0;
}