#include <iostream> 
#include <fstream> 
#include <vector>

using namespace std; 

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

int n, sol;
int dp[16005], viz[16005];
vector < int > L[16005];

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

void DFS(int nod)
{
    viz[nod] = 1;
    for(int i = 0; i < L[nod].size(); i++)
    {
        int nnod = L[nod][i];
        if(viz[nnod] == 0)
        {
            DFS(nnod);
        }
        if(dp[i] > 0)
        {
            dp[nod] += dp[i];
        }
    }
    sol = max(sol, dp[nod]);
}

int main()
{ 
    citire();
    for(int i = 1; i <= n; i++)
    {
        if(viz[i] == 0)
        {
            DFS(i);
        }
    }
    fout << sol;
    return 0;
}