#include<cstdio>
#include<vector>
using namespace std;
const int MAXN=16005;
int n,SOL_MAX=-160001;
int f[MAXN],optim[MAXN];
bool viz[MAXN];
vector<int> G[MAXN];
void dfs_visit(int u)
{
    viz[u]=true;
    optim[u]=f[u];
    for (vector<int>::iterator v=G[u].begin(); v!=G[u].end(); ++v)
    {
        if (!viz[*v])
        {
            dfs_visit(*v);
            if (optim[u]<optim[u]+optim[*v])
            {
                optim[u]=optim[u]+optim[*v];
                if (optim[u]>SOL_MAX)
                    SOL_MAX=optim[u];
            }
        }
    }
}
int main()
{
    int i,x,y;
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
    for (i=1; i<=n; ++i)
    {
        scanf("%d",&f[i]);
        SOL_MAX=max(SOL_MAX,f[i]);
    }
    for (i=1; i<=n-1; ++i)
    {
        scanf("%d%d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs_visit(1);
    printf("%d\n",SOL_MAX);
    return 0;
}