#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;

#define NMAX 16001

vector<int> arb[NMAX];
int n;
int v[NMAX];
int d[NMAX];
int tata[NMAX];

#define pb push_back

void citire()
{
    scanf("%d ",&n);
    for(int i=1;i<=n;i++)
        scanf("%d ",&v[i]);
    for(int i=1;i<n;i++)
    {
        int x,y;
        scanf("%d %d ",&x,&y);
        arb[x].pb(y);
        arb[y].pb(x);
    }
}
bool viz[NMAX];

void tati()
{
    queue<int>q;
    q.push(1);
    viz[1]=1;

    for(int i=1;i<=n;i++)
        d[i]=v[i];

    while(!q.empty())
    {
        int nod = q.front();
        q.pop();
        int suma = v[nod];
        for(vector<int>::iterator it=arb[nod].begin();it!=arb[nod].end();it++)
        {
            if(!viz[*it])
            {
                if(d[*it]>0)
                    suma += d[*it];
                viz[*it]=1;
                q.push(*it);
            }
        }
        d[nod]=suma;
    }
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);

    citire();
    tati();
    printf("%d\n",*max_element(d,d+n+1));
    return 0;
}