#include <fstream>
#include <vector>
#include <bitset>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
const int NMAX=16000;
vector <int>G[NMAX+5];
bitset <NMAX+5>viz;
int cost[NMAX+5];
void dfs(int nod)
{
  int i;
  viz[nod]=1;
  for(i=0;i<G[nod].size();i++)
  {
      if(viz[G[nod][i]]==0)
      {
        dfs(G[nod][i]);
        cost[nod]=max(cost[nod], cost[G[nod][i]]+cost[nod]);
      }
  }
}
int main()
{
     int i, n, x, y, sol;
     fin>>n;
     for(i=1;i<=n;i++)
        fin>>cost[i];
     for(i=1;i<=n-1;i++)
     {
         fin>>x>>y;
         G[x].push_back(y);
         G[y].push_back(x);
     }
     dfs(1);
     sol=cost[1];
     for(i=2;i<=n;i++)
        sol=max(sol, cost[i]);
     fout<<sol<<"\n";

    return 0;
}