#include <fstream>
#include <vector>

using namespace std;

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

const int N = 16000;

vector<int> a[N + 1];
int val[N + 1], sume[N + 1];
bool viz[N + 1];
int n;


void dfs(int x)
{
    viz[x] = true;
    sume[x] = val[x];
    for(auto y:a[x])
    {
        if(!viz[y])
        {
            dfs(y);
            if(sume[y] > 0)
            {
                sume[x] += sume[y];
            }
        }
    }
}

int main()
{
    in >> n;
    for(int i = 1; i <= n; i++)
    {
        in >> val[i];
    }
    for(int i = 0; i < n - 1; i++)
    {
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    int valMax = sume[1];
    for(int i = 1; i <= n; i++)
    {
        valMax = max(valMax, sume[i]);
    }
    out << valMax;
    out.close();
    in.close();
}