The set RBT of Red-Black Trees is defined recursively as follows: Base cases: (red) e RBT, and (black) e RBT. Constructor cases: A, B are RBT's, then if A, B start with black, then red, A, B is an RBT. if A. B start with red, then(black, A, B is an RBT. For any RBT T, let , be the number of red labels in T br be the number of black labels in T. and Prove that nT If T starts with a red label, then