#include <fstream>
#include <vector>
#include <climits>

using namespace std;

const int Nmax = 16005;

int n, val[Nmax], max_sum[Nmax];
vector<int> L[Nmax];

void dfs(int node, int father) {
    max_sum[node] = val[node];
    for(int son : L[node]) {
        if(son != father) {
            dfs(son, node);
            if(max_sum[son] > 0) {
                max_sum[node] += max_sum[son];
            }
        }
    }
}

int main() {
    ifstream fin("asmax.in");
    ofstream fout("asmax.out");
    fin >> n;
    for(int i = 1; i <= n; i++) {
        fin >> val[i];
    }
    for(int i = 1; i < n; i++) {
        int x, y;
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1, 0);
    int sol = INT_MIN;
    for(int i = 1; i <= n; i++) {
        sol = max(sol, max_sum[i]);
    }
    fout << sol;
}