const int N = 6005;
vector<int>v[N]; //邻接表
int happy[N]; //快乐值
bool has_father[N]; //找到根节点
int f[N][2];
void dfs(int u) {
  f[u][1] = happy[u];
  for (int i = 0; i < v[u].size();++i) {
    int j = v[u][i]; //当前节点的子节点
    dfs(j); // 先递归 后计算
    f[u][0] += max(f[j][0], f[j][1]); // 状态转移
    f[u][1] += f[j][0]; // 状态转移
  }
}
int main() {
  int n;cin >> n;
  for (int i = 1; i <= n;++i)cin >> happy[i];
  for (int i = 1;i < n;++i) { //读入树
    int a, b;cin >> a >> b;
    v[b].push_back(a);
    has_father[a] = true;
  }
  int root = 1;
  while (has_father[root])++root; //找到根节点
  dfs(root);
  printf("%d\n", max(f[root][0], f[root][1]));
}