#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <cmath>

using namespace std;

#define file_in "asmax.in"
#define file_out "asmax.out"

#define nmax 16010

int n;
vector<int> G[nmax];
int smin,nr,m[nmax],q[nmax];
int viz[nmax];
int v[nmax];

void citire()
{

    int i,a,b;

    freopen(file_in,"r",stdin);
    freopen(file_out,"w",stdout);

    scanf("%d", &n);
    for (i=1;i<=n;++i)
         scanf("%d", &v[i]);
    for (i=1;i<n;++i)
    {
        scanf("%d %d", &a, &b);

        G[a].push_back(b);
        G[b].push_back(a);
    }

}

void dfs(int nod)
{
    m[nod]=v[nod];
    if (viz[nod])
        return ;

    viz[nod]=1;

    int i;
    for (i=0;i<G[nod].size();++i)
         if (!viz[G[nod][i]])
         {
             dfs(G[nod][i]);
             if (m[G[nod][i]]>0)
             m[nod]+=m[G[nod][i]];
         }
}

void solve()
{
    int i;

      dfs(1);
     int maxx=-100000;
     for (i=1;i<=n;++i)
          if (m[i]>maxx) maxx=m[i];
     printf("%d\n", maxx);
}

int main()
{
    citire();
    solve();

    fclose(stdin);
    fclose(stdout);

    return 0;
}