#include <bits/stdc++.h>
#define oo -2e9
using namespace std;

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

int n , viz[16005] , val[16005] , a[16005] , sum , mx , i;
vector<int> L[16005];

void DFS(int nod)
{
    viz[nod] = 1;
    a[nod] = val[nod];
    for(int w : L[nod])
        if(!viz[w])
        {
            DFS(w);
            if(a[w] > 0) a[nod] += val[w];
        }
    if(mx < a[nod]) mx = a[nod];
    if(a[nod] < 0) a[nod] = 0;
}

int main()
{
    int j;
    fin >> n;
    for(i = 1;i <= n;i++)
        fin >> val[i];
    while(fin >> i >> j)
    {
        L[i].push_back(j);
        L[j].push_back(i);
    }
    DFS(1);
    fout << mx;
    return 0;
}
/**
1 2 3 4 5  6 7 8 9
1 4 2 1 -1 3 3 2 3
*/