#include <fstream>
#include <vector>
#define DIM 16001
using namespace std;
ifstream fin ("asmax.in");
ofstream fout ("asmax.out");
int n,i,j,x,y,v[DIM],d[DIM],sol,marcat[DIM];
vector <int> L[DIM];
void dfs (int nod){
    marcat[nod] = 1;
    int s = 0;
    for (int i=0;i<L[nod].size();i++){
        int fiu = L[nod][i];
        if (marcat[fiu] == 0){
            dfs (fiu);
            if (d[fiu] > 0)
                s+=d[fiu];
        }
    }


    d[nod] = max (v[nod],v[nod]+s);// d[fii sai])
    sol = max (sol,d[nod]);


}
int main (){

    fin>>n;
    for (i=1;i<=n;i++)
        fin>>v[i];
    for (i=1;i<n;i++){
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs (1);
    fout<<sol;




    return 0;
}