#include <fstream>
#include <vector>

using namespace std;

const int MAX_N = 16000;
bool viz[MAX_N+1];
int scor[MAX_N+1], v[MAX_N+1];
vector <int> a[MAX_N+1];

void dfs(int x) {
    viz[x] = true;
    scor[x] = v[x];
    for(auto y:a[x]){
        if(!viz[y]){
            dfs(y);
            if(scor[y] > 0){
                scor[x] += scor[y];
            }
        }
    }
}

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

    int n;
    fin >> n;

    for (int i = 1; i <= n; ++i) {
        fin >> v[i];
    }

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

    dfs(1);
    int maxi = 0;
    for (int i = 1; i <= n; ++i) {
        maxi = max(maxi, scor[i]);
    }
    fout << maxi << endl;

    fin.close();
    fout.close();

    return 0;
}