#include <fstream>
#include <vector>
using namespace std;
ifstream fin ("asmax.in");
ofstream fout ("asmax.out");
int n,i,x,y,minc,k,sol,viz[16005],s[16005];
vector <int> v[16005];
void dfs (int nod)
{
    viz[nod]=1;
    for (int i=0; i<v[nod].size (); i++)
    {
        int vecin=v[nod][i];
        if (viz[vecin]==0)
        {
            dfs (vecin);
            if (s[vecin]>0)
                s[nod]+=s[vecin];
        }
    }
    sol=max (sol,s[nod]);
}
int main()
{
    fin>>n;
    fin>>s[1];
    sol=s[1];
    for (i=2; i<=n; i++)
    {
        fin>>s[i];
        sol=max (sol,s[i]);
    }
    for (i=1; i<n; i++)
    {
        fin>>x>>y;
        v[x].push_back (y);
        v[y].push_back (x);
    }
    dfs (1);
    fout<<sol;
    return 0;
}