#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
#define nmax 16001

vector <int> v[nmax];
int n,val[nmax],sum[nmax],valmax=-(1<<20);
bool viz[nmax]={false};

void dfs(int nod)
{
    int j,x;
    viz[nod]=true;
    sum[nod]=val[nod];
    for (j=0;j<v[nod].size();j++)
    {
        x=v[nod][j];
        if (!viz[v[nod][j]])
        {
            dfs(x);
            sum[nod]=max(sum[nod],sum[nod]+sum[x]);
        }
    }
    valmax=max(valmax,sum[nod]);
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    int x,y,i;
    scanf("%d",&n);
    for (i=1;i<=n;i++)
        scanf("%d",&val[i]);
    for (i=1;i<n;i++)
    {
        scanf("%d %d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    printf("%d",valmax);
    return 0;
}