#include <iostream>
#include <fstream>
#include <vector>
#include <climits>
#include <bitset>
#define dim 16001
using namespace std;
ifstream fin("asmax.in");
ofstream fout("asmax.out");
int maxx=-INT_MAX,n,i,v[dim],x,y;
vector<int> L[dim];
bitset<dim> fr;
int dfs(int nod)
{
    fr[nod]=1;
    int s=v[nod];
    for(auto it:L[nod]){
        if(!fr[it]){
            int val=dfs(it);
            if(val>0)
                s+=val;
        }
    }
    maxx=max(maxx,s);
    return s;
}
int main()
{
    fin>>n;
    for(i=1; i<=n; i++)
    {
        fin>>v[i];
    }

    for(i=1; i<n; i++)
    {
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1);
    fout<<maxx;
}