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

using namespace std;

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

const int DIM = 16010;
int n, x, y, sol = INT_MIN;
int nums[DIM], sum[DIM];
vector<int> v[DIM];
bool vis[DIM];

void dfs(int node) {
    vis[node] = true;
    sum[node] = nums[node];
    for (int i = 0; i < v[node].size(); i++) {
        if (!vis[v[node][i]]) {
            dfs(v[node][i]);
            if (sum[v[node][i]] > 0)
                sum[node] += sum[v[node][i]];
        }
    }
    sol = max(sol, sum[node]);
}

int main() {
    fin >> n;
    for (int i = 1; i <= n; i++)
        fin >> nums[i];
    for (int i = 1; i < n; i++) {
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    dfs(1);

    fout << sol;

    return 0;
}