#include <bits/stdc++.h>

using namespace std;

ifstream f("asmax.in");
ofstream g("asmax.out");

const int NMAX = 16000;
int v[NMAX + 1], dp[NMAX + 1], vis[NMAX + 1];
vector<int> G[NMAX + 1];

void dfs(int node) {
    vis[node] = 1;
    for(auto next : G[node]) {
        if(!vis[next]) {
            dfs(next);
            if(dp[next] > 0) {
                dp[node] += dp[next];
            }
        }
    }
}

int main() {
    int n;
    f >> n;
    for(int i = 1; i <= n; i++) {
        f >> v[i];
        dp[i] = v[i];
    }
    for(int i = 1; i < n; i++) {
        int x, y;
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1);
    int mx = 0;
    for(int i = 1; i <= n; i++) {
        mx = max(mx, dp[i]);
    }
    g << mx;
    return 0;
}