#include <fstream>
#include <climits>
#include <vector>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
#define nmax 16001
vector<int> a[nmax];
int n, v[nmax], maxi = INT_MIN;
bool use[nmax];
void dfs(int nod) {
    use[nod] = true;
    for (int i = 0; i < a[nod].size(); ++i) {
        if (!use[a[nod][i]]) {
            dfs(a[nod][i]);
            if (v[a[nod][i]] > 0) v[nod] += v[a[nod][i]];
        }
    }
}
int main()
{
    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;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    for (int i = 1; i <= n; ++i) maxi = max(maxi, v[i]);
    g << maxi << '\n';
    return 0;
}