#include <iostream>
#include <cstdio>
#include <vector>
using namespace std;
int n,vVal[16005],dp[16005],viz[16005];
vector <int> G[16005];
void citire()
{
    scanf("%d",&n);
    for(int i=1; i<=n; i++)
    {
        scanf("%d",&vVal[i]);
    }
    int aux1,aux2;
    for(int i=1; i<n; i++)
    {
        scanf("%d%d",&aux1,&aux2);
        G[aux1].push_back(aux2);
        G[aux2].push_back(aux1);
    }
}
int DFS(int nod)
{
    if(dp[nod])
        return dp[nod];

    viz[nod]=1;
    vector <int> ::iterator IT;
    dp[nod]=vVal[nod];
    int aux;
    for(IT=G[nod].begin(); IT!=G[nod].end(); IT++)
    {
        if(viz[*IT]==0)
        {
            aux=DFS(*IT);
            if(aux>0)
            {
                dp[nod]+=aux;
            }
        }
    }
    return dp[nod];
}
int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    citire();
    DFS(1);
    int rasp=-0x3f3f3f;
    for(int i=1;i<=n;i++)
        rasp=max(rasp,dp[i]);
    printf("%d",rasp);
    return 0;
}