#include <bits/stdc++.h>
#define MAXN 16000
#define INF 1000000000

using namespace std;

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

vector <int> graf[MAXN + 1];
int val[MAXN + 1], dp[MAXN + 1], mx;

void DFS(int nod){
    int i, vec;

    dp[nod] = val[nod];

    for(i = 0; i < graf[nod].size(); i++){
        vec = graf[nod][i];
        if(dp[vec] == -INF){
            DFS(vec);
            if(dp[vec] > 0){
                dp[nod] += dp[vec];
            }
        }
    }
    mx = max(mx, dp[nod]);
}

int main()
{
    int n, i, a, b;

    fin >> n;
    for(i = 1; i <= n; i++){
        fin >> val[i];
        dp[i] = -INF;
    }
    for(i = 1; i < n; i++){
        fin >> a >> b;
        graf[a].push_back(b);
        graf[b].push_back(a);
    }

    mx = -INF;
    DFS(1);
    fout << mx << "\n";
    return 0;
}