#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream cin("asmax.in");
ofstream cout("asmax.out");
int n,val[16001],i,x,y,ok,r;
bool fol[16001];
vector<int> graf[16001];
queue<int> coada;
int main()
{
   cin>>n;
   for(i=1; i<=n; i++)
    cin>>val[i];
   for(i=1; i<=n-1; i++)
   {
       cin>>x>>y;
       graf[x].push_back(y);
       graf[y].push_back(x);
   }
   coada.push(1); fol[1]=1;
   while(!coada.empty())
   {
       ok=coada.front(); coada.pop();
       for(i=0; i<graf[ok].size(); i++)
       {
           if(!fol[graf[ok][i]])
           {
               fol[graf[ok][i]]=1;
               coada.push(graf[ok][i]);
               if(val[graf[ok][i]]>0)
                    val[ok]+=val[graf[ok][i]];
           }
       }
   }
   for(i=1; i<=n; i++)
    r=max(r,val[i]);
   cout<<r;

}