#include    <fstream>
#include    <vector>
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");

const int Max = 16005;
const int oo =  -(1<<30);

vector <int> V[Max];

int n, Val[Max],Sum[Max],Result= -(1<<30);
bool viz[Max];

void DFS(int nod)
{
    viz[nod] = true;
    Sum[nod] = Val[nod];

    for(int i=0; i<(int)V[nod].size(); i++)
    {
        int vecin = V[nod][i];
        if(!viz[vecin])
        {
            DFS(vecin);
            Sum[nod] = max(Sum[nod], Sum[nod] + Sum[vecin]);
        }
    }

    Result = max(Result, Sum[nod]);
}
void Read()
{
    in>>n;
    for(int i=1;i<=n; i++)
        in>>Val[i];

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

int main()
{
    Read();
    DFS(1);
    out<<Result;
    return 0;
}