#include <fstream>
#include <vector>
#define DIM 16002

using namespace std;

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

vector <int> v[DIM];
int viz[DIM],n;
long long smax=-DIM,a[DIM];
bool t[DIM];
void DFS(int x){
    viz[x]=1;
    for(int i=0;i<v[x].size();i++)
        if(!viz[v[x][i]]){
            DFS(v[x][i]);
            if(a[v[x][i]]>0)
                a[x]+=a[v[x][i]];
        }
    if(a[x]>smax)
        smax=a[x];

}
int main(){
    fin>>n;
    for(int i=1;i<=n;i++){
        fin>>a[i];
    }
    for(int i=1;i<n;i++){
        int x,y;
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    DFS(1);
    fout<<smax;
    fin.close();fout.close();
    return 0;
}