Power Tree

Ada is one of the best hairdressers in ChefLand. She invented a very cool hair style and named it "power tree". A power tree with degree $l$ — let's denote it by $PT(l)$ — is a directed graph, which can be constructed recursively as follows: - $PT(0)$ consists of a single node. - For $l \gt 0$: - Create one node $u$ — the *root* of power tree $PT(l)$. - Construct all power trees wit