#include<bits/stdc++.h>
 
using namespace std;
 
int n, cost[16100], x, y, viz[16000],rs;
vector<int> a[16100];
int dfs(int x)
{
    viz[x] = 1;
    int rez=0;
    for (vector<int>::iterator it = a[x].begin(); it != a[x].end(); it++)
    {
        if (!viz[*it])
        {
            rez += dfs(*it);
        }
    }
    rs = max(rs,max(rez + cost[x], max(0,cost[x])));
    return max(rez + cost[x], max(0,cost[x]));
}
int main()
{
    ifstream cin("asmax.in");
    ofstream cout ("asmax.out");
    cin >> n;
    int x = -1<<30;
    for (int i = 1; i <= n ; i++) {cin >> cost[i]; x = max(x,cost[i]);}
    for (int i = 1; i <= n-1; i++)
    {
        cin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);      
    }
    dfs(1);
    cout << max(x,rs);
}