#include <fstream>
#include <vector>

using namespace std;

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

const int N=16001;

int val[N],scor[N];
vector<int> a[N];
bool viz[N];

void dfs(int nod)
{
    viz[nod]=1;
    scor[nod]=val[nod];
    for(int i=0; i<a[nod].size(); i++)
    {
        if(viz[a[nod][i]]==0)
        {
            dfs(a[nod][i]);
            if(scor[a[nod][i]]>0)
            {
                scor[nod]+=scor[a[nod][i]];
            }
        }
    }
}

int main()
{
    int n;
    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;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);
    int maxs=0;
    for(int i=1; i<=n; i++)
    {
        if(scor[i]>maxs)
        {
            maxs=scor[i];
        }
    }
    out<<maxs;
    return 0;
}