#include <fstream>
#include <vector>

using namespace std;

const int NMAX = 16000;

vector <int> v[1 + NMAX];

int val[1 + NMAX];
int dp[1 + NMAX];
bool viz[1 + NMAX];

void dfs(int x)
{
  viz[x] = true;

  dp[x] = val[x];
  for(int i = 0; i < v[x].size(); i++)
  {
    if (!viz[v[x][i]])
    {
      dfs(v[x][i]);
      if (dp[v[x][i]] > 0)
      {
        dp[x] += dp[v[x][i]];
      }
    }
  }
}

int main()
{
  ifstream in("asmax.in");
  ofstream out("asmax.out");

  int n, a, b, sol = -1000;

  in >> n;
  for (int i = 1; i <= n; i++)
  {
    in >> val[i];
  }
  for (int i = 1; i < n; i++)
  {
    in >> a >> b;

    v[a].push_back(b);
    v[b].push_back(a);
  }

  dfs(1);

  for (int i = 1; i <= n; i++)
  {
    sol = max(sol, dp[i]);
  }

  out << sol;

  return 0;
}