#include <iostream>
#include <fstream>
#include <algorithm>
#include <vector>
using namespace std;

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

const int N=16001;

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

int n,maxim;

void citire()
{
    int x,y;
    for(int i=1; i<n; ++i)
    {
        in>>x>>y;
        a[y].push_back(x);
        a[x].push_back(y);
    }
    in.close();
}
void dfs(int x)
{
    viz[x]=true;
    scor[x]=s[x];
    if(scor[x]>maxim) maxim=scor[x];
    for(auto y: a[x])
    {
        if(!viz[y])
        {
            dfs(y);
            if(scor[y]>0)
            {
                scor[x]+=scor[y];
                if(scor[x]>maxim)maxim=scor[x];
            }
        }
    }
}
int main(int x)
{
    in>>n;
    for(int i=1; i<=n; ++i) in>>s[i];
    citire();
    for(int i=1; i<=n; ++i)
    {
        if(!viz[i]) dfs(i);
    }

    out<<maxim;
    return 0;
}