printf ("%lu+%lu/%d", node->n_zeros, node->n_ones, node->abt_node.level);
if (node->abt_node.down[0] || node->abt_node.down[1])
{
printf ("%lu+%lu/%d", node->n_zeros, node->n_ones, node->abt_node.level);
if (node->abt_node.down[0] || node->abt_node.down[1])
{