/// copiii astia s-au haladit, asta-i subiectul
#include <fstream>
#include <vector>

using namespace std;

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

const int maxN = 16005;
int n, v[maxN], ans;
vector <int> G[maxN];

int dfs(int nod, int tata) {
    int best = v[nod];
    for (int vecin : G[nod]) {
        if (vecin == tata) {
            continue;
        }
        int val = dfs(vecin, nod);
        if (val > 0) {
            best += val;
        }
    }
    ans = max(ans, best);
    return best;
}

int main()
{
    fin >> n;
    for (int i = 1; i <= n; i++) {
        fin >> v[i];
    }
    for (int i = 1; i < n; i++) {
        int x, y;
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    ans = -1e9;
    dfs(1, 0);
    fout << ans;
    return 0;
}