#include <fstream>
#include <vector>

using namespace std;

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

const int N = 16005;

vector <int> a[N];

int n;
int cost[N];
int sum[N];

bool viz[N];

inline int maxim (int a, int b)
{
    if (a > b)
        return a;
    return b;
}

void read()
{
    in >> n;

    for (int i = 1; i <= n; i++) {
        in >> cost[i];
    }

    for (int i = 1; i < n; i++) {
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
}

void dfs(int nod)
{
    viz[nod] = true;
    sum[nod] = cost[nod];

    for (int i = 0; i < a[nod].size(); i++) {
        int y = a[nod][i];
        if (!viz[y]) {
            dfs(y);
            if(sum[y] > 0) {
                sum[nod] += sum[y];
            }
        }
    }
}

int main()
{
    read();
    dfs(1);

    int sumaMaxima = -1001;
    for (int i = 1; i <= n; i++) {
        sumaMaxima = maxim(sumaMaxima, sum[i]);
    }
    out << sumaMaxima << "\n";

    return 0;
}