#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <climits>
#include <algorithm>
#define LOWER_THAN_BOUNDARY -2000
using namespace std;

ifstream fin("asmax.in");
ofstream fout("asmax.out");


int t, n, m, x, y, d, cost, start;
int maxVal = LOWER_THAN_BOUNDARY;
vector<vector<int>> edges;

vector<int> val;
vector<bool> visited;

int DFS(const int& currNode)
{
   visited[currNode] = true;
   int currNodeVal = val[currNode-1]; // indexing starts from 0
   for(auto& neigh: edges[currNode])
   {
       if(!visited[neigh])
       {
           int backtrackVal = DFS(neigh);
           if(backtrackVal + currNodeVal > currNodeVal)
               currNodeVal += backtrackVal;
       }
   }
   maxVal = max(currNodeVal, maxVal);
   return currNodeVal;
}

int main()
{
    fin >> n;

    for(int i = 1; i <= n; i++)
    {
      fin >> x;
      val.push_back(x);
    }
    visited.resize(n+1, false);
    edges.resize(n+1);
    for(int i = 0; i < n-1; i++)
    {
        fin >> x >> y;
        edges[x].push_back(y);
        edges[y].push_back(x);
    }
    DFS(1);
    fout << maxVal;
    return 0;
}