#include <fstream>
#include <bitset>
#include <vector>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
bitset <16002> viz;
int n,i,val[16002],x,y,MAX;
vector <int> v[16002];
void dfs(int i)
{
    int j;
     viz[i]=true;
     for (j=0;j<v[i].size();j++)
        if (viz[v[i][j]]==false)
     {
         dfs(v[i][j]);
         if (val[v[i][j]]>0)
            val[i]+=val[v[i][j]];
     }
}
int main()
{
    f>>n;
    for (i=1;i<=n;i++)
        f>>val[i];
    for (i=1;i<=n-1;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (i=1;i<=n;i++)
        MAX=max(val[i],MAX);
    g<<MAX;
    return 0;
}