#include <bits/stdc++.h>
using namespace std;
const int NMAX = 16000;
vector<int> G[NMAX + 1];
int vis[NMAX + 1];
int dp[NMAX + 1], v[NMAX + 1];
vector<int> L[NMAX + 1];

void dfs(int node) {
    vis[node] = 1;
    for(auto vec : G[node]) {
        if(!vis[vec]) {
            dfs(vec);
            if(dp[vec] > 0) {
                dp[node] += dp[vec];
            }
        }
    }
}

int main()
{
   int n;
   cin >> n;
   for(int i=1; i<=n; i++)
   {
       cin >>v[i];
       dp[i]=v[i];
   }
   for(int i=1; i<n; i++)
   {
       int x, y;
       cin >> x >> y;
       G[x].push_back(y);
       G[y].push_back(x);
   }
   dfs(1);

    int sol = -1e9;
    for(int i = 1; i <= n; i++) {
        sol = max(sol, dp[i]);
    }
    cout << sol;
    return 0;
}