#include <fstream>
#include <vector>

using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");

const int N = 16005;
vector <int> vecini[N];
bool viz[N];
int val[N], maxim;

int dfs(int nod)
{
    viz[nod] = true;
    int maximus = val[nod], x;
    vector <int> ::iterator it;
    for(it = vecini[nod].begin(); it < vecini[nod].end(); ++it)
        if(viz[*it] == false)
        {
            x = dfs(*it);
            if(x > 0)
                maximus += x;
        }
    if(maximus > maxim)
        maxim = maximus;
    return maximus;
}

int main()
{
    int n, i, a, b;
    in >> n;
    for(i = 1; i <= n; i++)
        in >> val[i];
    maxim = val[1];
    for(i = 1; i < n; i++)
    {
        in>> a >> b;
        vecini[a].push_back(b);
        vecini[b].push_back(a);
    }
    int d = dfs(1);
    out <<maxim;

    return 0;
}