#include<bits/stdc++.h>
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
int n,t,q,i,j,a[17001],v[17001],maxim,x,y;
vector <int> G[17001];
void dfs(int nod)
{
    v[nod]=1;
    for(int i=0;i<G[nod].size();i++)
    {
        if(v[G[nod][i]]==0)
        {

            dfs(G[nod][i]);
            a[nod]=max(a[nod],a[G[nod][i]]+a[nod]);
        }
    }

    maxim=max(maxim,a[nod]);
}
int main()
{
    f>>n;
    for(i=1;i<=n;i++)
    {
        f>>a[i];
    }
    for(i=1;i<n;i++)
    {
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1);
    g<<maxim;
    return 0;
}