#include <bits/stdc++.h>
#define val 16005
using namespace std;
vector <int> L[val];
int n, d[val];
int dp[val];
int viz[val];
void Citire()
{   int i, x, y;
    ifstream fin("asmax.in");
    fin >> n ;
    for(i = 1; i <= n; i ++)
        fin >> d[i];
    for(i = 1; i < n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }


}
void DFS(int k)
{
    viz[k] = 1;
    dp[k] = d[k];

    for(int i = 0 ;i < L[k].size(); i++)
        if(viz[L[k][i]] == 0)
        {   dp[k]=max(dp[k],dp[k] + d[L[k][i]]);
            DFS(L[k][i]);
        }
}

int main()
{
    int i;
    Citire();
    DFS(1);
    int maxim = dp[1];
    for(i = 2; i <= n; i++)
        maxim = max(maxim, dp[i]);
    ofstream fout("asmax.out");
    fout << maxim;
    return 0;
}