#include <bits/stdc++.h>
#define Nmax 16050

using namespace std;

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

int N, a[Nmax], dp[Nmax], fr[Nmax];
vector <int> L[Nmax];
bool used[Nmax];

inline void DFS(int nod)
{
    dp[nod] = a[nod];
    used[nod] = 1;
    for(auto it : L[nod])
        if(!used[it])
        {
            DFS(it);
            dp[nod] = max(dp[it] + dp[nod], dp[it]);
        }
}

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

inline void Solve()
{
    int i, ans;
    for(i = 1; i <= N; i++)
        if(fr[i] == 1)
        {
            DFS(i);
            break;
        }
    ans = dp[1];
    for(i = 2; i <= N; i++)
        ans = max(ans, dp[i]);
    fout << ans << "\n";
    fout.close();
}

int main()
{
    Read();
    Solve();
    return 0;
}