#include <bits/stdc++.h>

using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
const int nmax = 16005;
int N,dp[nmax],ans;
bool viz[nmax];
vector < int > L[nmax];


inline void Read()
{
    int i,x,y;
    fin >> N;
    for(i = 1; i <= N; i++) fin >> dp[i];
    for(i = 1; i < N; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

inline void DFS(int nod, int tata)
{
    viz[nod] = true;
    for(auto it : L[nod])
    {
        if(it != tata)
        {
            if(!viz[it]) DFS(it,nod);
            if(dp[it] > 0) dp[nod] += dp[it];
        }
    }
    ans = max(ans,dp[nod]);
}


int main()
{
    Read();
    DFS(1,0);
    fout << ans << "\n";
    fout.close();
    return 0;
}