#include <fstream>
#include <vector>
#include <climits>

using namespace std;

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

const int N = 16001;

int n, sum[N];
bool viz[N];
vector <int> a[N];

void citire() {
    int x, y;
    in >> n;

    for (int i = 1; i <= n; i++) in >> sum[i];

    for (int i = 0; i < n - 1; i++) {
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }

    in.close();
}

void dfs(int x) {
    viz[x] = true;

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

int main()
{
    int m = INT_MIN;
    citire();

    for (int i = 1; i <= n; i++) {
        if (!viz[i]) dfs(i);
    }

    for (int i = 1; i <= n; i++) m = max(m, sum[i]);

    //for (int i = 1; i <= n; i++) out << sum[i] << ' ';
    //out << '\n';
    out << m;
    out.close();
}