#include <fstream>
#include <vector>
using namespace std;

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

const int N = 100;
vector <int> a[N + 1];
int scor[N + 1], vizitat[N + 1], n, val[N + 1], maxim;

void dfs(int x)
{
    vizitat[x] = 1;
    scor[x] = val[x];
    for(auto i : a[x])
        if(!vizitat[i])
        {
            dfs(i);
            if(scor[i] > 0)
                scor[x] += scor[i];
        }
}

int main()
{
    cin >> n;
    for(int i = 1; i <= n; i++)
        cin >> val[i];
    for(int i = 1; i < n; i++)//un graf are n-1 muchii
    {
        int x, y;
        cin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    for(int i = 1; i <= n; i++)
        if(scor[i] > maxim)
            maxim = scor[i];
    cout << maxim << "\n";
    return 0;
}