#include<fstream>
#include<vector>
#include<algorithm>
using namespace std;
ifstream in("asmax.in");
ofstream out("asmax.out");

#define Nmax 16005
vector <int> v[Nmax];
int N, M, val[Nmax] , ct[Nmax]={0}, viz[Nmax]={0}, maxx=0;

void Dfs(int nod)
{
    viz[nod]=1;
    ct[nod]=val[nod];
    for(int i=0; i<v[nod].size(); ++i)
    {
        int x=v[nod][i];
        if(viz[x]==0)
        {
            Dfs(x);
            ct[nod]= max(ct[nod], ct[nod] + ct[x]);
        }
    }
    maxx= max( maxx, ct[nod]);
}


int main ()
{
    int x, y;

    in>>N;

    for(int i=1;i<=N;i++)
        in>>val[i];

    for(int i=1;i<=N-1;i++)
    {
        in>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    Dfs(1);

    out<<maxx<<'\n';
    return 0;
}