//#include <iostream>
#include <bits/stdc++.h>
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");
const int Max=16005;
vector < int > v[Max];
int n,sum[Max],viz[Max];
void citire()
{
   in>>n;
   for(int i=1;i<=n;i++)
    in>>sum[i];
   for(int i=1;i<n;i++)
   {
       int x,y; in>>x>>y;
       v[x].push_back(y);
       v[y].push_back(x);
   }
}
void dfs(int nod)
{
    viz[nod]=1;
    for(int j=0;j<v[nod].size();j++)
    {
        int vecin=v[nod][j];
        if(!viz[vecin])
        {
            dfs(vecin);
            if(sum[vecin]>0)
                sum[nod]+=sum[vecin];
        }
    }
}
int main()
{
    citire();
    dfs(1); int Max=INT_MIN;
    for(int i=1;i<=n;i++)
      if(sum[i]>Max)
      Max=sum[i];
    out<<Max;
    return 0;
}