#include <fstream>
#include <vector>
using namespace std;
const int N = 16005;
const int MIN = -999999999;
ifstream f("asmax.in");
ofstream g("asmax.out");
int n;
int d[N];
bool viz[N];
vector <int> V[N];
int MAX = MIN;
int dfs(int x)
{
    viz[x] = 1;
    for(int i = 0 ; i< V[x].size(); i++)
    {
        int num = V[x][i];
        if(viz[num] == 0)
        {
            d[x] = max(d[x],d[x]+dfs(num));
        }
    }
    return d[x];
}
int main()
{
    f>>n;
    for(int i = 1;i <=n; i++)
    {
        f>>d[i];
    }
    for(int i = 1; i < n; i++)
    {
        int x,y;
        f>>x>>y;
        V[x].push_back(y);
        V[y].push_back(x);
    }
    dfs(1);
    for(int i =1 ;i <= n; i++)
    {
        MAX = max(d[i],MAX);
    }
    g<<MAX;
    f.close();
    g.close();
    return 0;
}