#include <fstream>
#include <vector>

using namespace std;

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

vector<int> v[16001];
int n,a[16001],sum[16001],smax=0;
bool used[16001];

int dfs(int x)
{
    used[x] = true;
    sum[x] = a[x];
    for(unsigned int i=0;i<v[x].size();i++)
    {
        if(!used[v[x][i]])
        {
            dfs(v[x][i]);
            if(sum[v[x][i]]>0)
                sum[x]+=sum[v[x][i]];
        }
    }


}



int main()
{
    int x,y;
    fin>>n;
    for(int i=1;i<=n;i++)
        fin>>a[i];
    for(int i=1;i<n;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    for(int i=1;i<=n;i++)
        if(smax<sum[i])
            smax = sum[i];
    fout<<smax<<'\n';


    fin.close();
    fout.close();
    return 0;
}