#include <bits/stdc++.h>

using namespace std;

int dp[16001];
int v[16001];
vector<int> m[16001];
int vis[16001];


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



int main()
{
    ifstream cin("asmax.in");
    ofstream cout("asmax.out");
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>v[i];
        dp[i]=v[i];
    }
    for(int i=1;i<n;i++)
    {
        int a,b;
        cin>>a>>b;
        m[a].push_back(b);
        m[b].push_back(a);
    }
    dfs(1);
    int sol = -1e9;
    for(int i = 1; i <= n; i++) {
        sol = max(sol, dp[i]);
    }
    cout<<sol;

    return 0;
}