#include <fstream>
#include <vector>
using namespace std;
ifstream f ("asmax.in");
ofstream g ("asmax.out");
const int nmax=16e3+3;
int val[nmax],sol=-nmax*1000-3,nod,n,cost[nmax],a,b;
vector <int> v[nmax];
void solve(int nod,int ant)
{
    val[nod]=cost[nod];
    for(int i=0;i<v[nod].size();++i)
    {
        if(v[nod][i]!=ant)
        {
            solve(v[nod][i],nod);
            if(val[v[nod][i]]>0) val[nod]+=val[v[nod][i]];
        }
    }
    sol=max(sol,val[nod]);
}
int main()
{
    f>>n;
    for(int i=1;i<=n;++i) f>>cost[i];
    for(int i=1;i<n;++i)
    {
        f>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    solve(1,0);
    g<<sol;
    return 0;
}