#include <algorithm>
#include <fstream>
#include <vector>

using namespace std;

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

vector <int> a[10000];
int scor[10000],s[10000];
bool viz[10000];
int n;

void citire()
{
    int x,y;
    for(int i=1; i<n; i++)
    {
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    in.close();
}

void dfs(int x)
{
    viz[x]=true;
    scor[x]=s[x];
    for(auto y:a[x])
    {
        if(!viz[y])
        {
            dfs(y);
            if(scor[y]>0)
            {
                scor[x]+=scor[y];
            }
        }
    }
}


int main()
{
    int i;
    in>>n;
    for(i=1 ; i<=n ; i++)
    {
        in>>s[i];
    }
    citire();
    dfs(1);
    sort(scor+1,scor+n+1);
    out<<scor[n];
    return 0;
}