#include <fstream>
#include <vector>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
const int NMAX = 16001;
int v[NMAX], val[NMAX], rez = -16000 * 1000;
vector<int> v2[NMAX];

void dfs(int nod, int t) {
    val[nod] += v[nod];
    for (int i : v2[nod]) {
        if (i != t) {
            dfs(i, nod);
            if (val[i] > 0) {
                val[nod] += val[i];
            }
        }
    }

    rez = max(rez, val[nod]);
}

int main() {
    int n;
    f >> n;
    for (int i = 1; i <= n; i++)
        f >> v[i];
    for (int i = 1; i < n; i++) {
        int x, y;
        f >> x >> y;
        v2[x].push_back(y);
        v2[y].push_back(x);
    }
    dfs(1, 0);
    g << rez;
    return 0;
}