#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
 
ifstream fin("asmax.in");
ofstream fout("asmax.out");
 
const int MaxN = 16001, Inf = 0x3f3f3f3f;
vector<int> arb[MaxN];
vector<int> smax;  // smax[x] suam maxima a unui subarbore cu radacina in x
vector<int> v;     // valorile asociate nodurilor
vector<bool> s;
int n;
 
void Read();
void Df(int x);
 
int main()
{
    Read();
    Df(1);
    int vmax = -Inf;
    for (int i = 1; i <= n; ++i)
        vmax = max(vmax, smax[i]);
     
    fout << vmax << '\n';
    fin.close();
    fout.close();
}
 
void Df(int x)
{
    s[x] = true;
    smax[x] = v[x];
    for (const int& y : arb[x])
        if ( !s[y] )
        {
            Df(y);
            if ( smax[y] > 0 )
                smax[x] += smax[y];
        }
}
 
void Read()
{
    fin >> n;
    v.resize(n + 1);
    s.resize(n + 1);
    smax.resize(n + 1);
    for (int i = 1; i <= n; ++i)
        fin >> v[i];
    int x, y;
    for (int i = 1; i < n; ++i)
    {
        fin >> x >> y;
        arb[x].push_back(y);
        arb[y].push_back(x);
    }
}