#include <fstream>
#include <vector>
#define NMAX 16005
using namespace std;

vector <int> v[NMAX];
int maxim,n,i,viz[NMAX],val[NMAX];
ifstream f("asmax.in");
ofstream g("asmax.out");
int dfs(int x){
    viz[x]=true;
    int max1=val[x];
    for(vector <int> ::iterator it=v[x].begin();it<v[x].end();++it)
        if(viz[*it]==false){
            int y=dfs(*it);
            if(y>0)
                max1+=y;
        }
    if(max1>maxim)
        maxim=max1;
    return max1;
}
int main()
{
    f>>n;
    for(i=1;i<=n;i++){
        f>>val[i];
    }
    maxim=val[1];
    for(i=1;i<n;i++){
        int x,y;
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

   int xx= dfs(1);
    g<<maxim;
    return 0;
}