#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
#define mp make_pair
#define CHECK(x) if(!(x)) return false;

#ifdef INFOARENA
#define ProblemName "asmax"
#endif

#define MCONCAT(A, B) A B
#ifdef ProblemName
#define InFile MCONCAT(ProblemName, ".in")
#define OuFile MCONCAT(ProblemName, ".out")
#else
#define InFile "fis.in"
#define OuFile "fis.out"
#endif

const int MAXN = 16010;
vector<int> G[MAXN];
bool viz[MAXN];
int v[MAXN];
int best = INT_MIN;

int DFS(int x) {
  viz[x] = true;
  int cand = v[x];
  for (const auto &it : G[x]) {
    if (viz[it])
      continue;
    int t = DFS(it);
    if (t > 0)
      cand += t;
  }
  best = max(best, cand);
  return cand;
}

int main() {
  assert(freopen(InFile, "r", stdin));
  assert(freopen(OuFile, "w", stdout));
  int N;
  scanf("%d", &N);
  for (int i = 0; i < N; ++i)
    scanf("%d", &v[i]);
  for (int i = 0; i < N - 1; ++i) {
    int a, b;
    scanf("%d%d", &a, &b);
    --a, --b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  DFS(0);
  printf("%d\n", best);
  return 0;
}