private Node Insert(Node p, int val)
{
if (p == null)
{
Node q = new BsTreeAvlCopy(val);
q.height = 1;
return(q);
}
if (val < p.val)
{
p.left = Insert(p.left, val);
}
else
{
p.right = Insert(p.right, val);
}
return(Balance(p));
}