#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
#define NMAX 16001
int val[NMAX],d[NMAX],s[NMAX]; //s = vizitat
vector <int> v[NMAX];
void dfs(int nod)
{
    int i;
    s[nod]=-1;
    d[nod]=val[nod];
    for(i=0;i<v[nod].size();i++)
    {
        if(s[v[nod][i]]==0)
        {
            dfs(v[nod][i]);
            if(d[v[nod][i]]>0)
                d[nod]+=d[v[nod][i]];
        }
    }
}
int main()
{
    int i,r,n,a,b;
    r=-17000000; //"artificiu"
    fin>>n;
    n++;
    for(i=1;i<n;i++)
        fin>>val[i];
    n--;
    for(i=1;i<n;i++)
    {
        fin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    n++;
    dfs(1);
    for(i=1;i<n;i++)
        if(d[i]>r) r=d[i];
    fout<<r;
}