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