#include <fstream>
#include <vector>
using namespace std;
ifstream cin("asmax.in");
ofstream cout("asmax.out");
int n,val[16001],i,x,y,ok,r=-100000000;
bool fol[16001];
vector<int> graf[16001];
void dfs(int ok)
{
   for(int i=0; i<graf[ok].size(); i++)
    {
     if(!fol[graf[ok][i]])
     {
        fol[graf[ok][i]]=1;
         if(val[graf[ok][i]]>0)
            val[ok]+=val[graf[ok][i]];
        dfs(graf[ok][i]);
      }
    }
}
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);
   }
   fol[1]=1; dfs(1);
   for(i=1; i<=n; i++)
    r=max(r,val[i]);
   cout<<r;

}