Find the Context Free Grammar Let $\Sigma = \{a, b\}$. For each of the following languages, find a grammar that generates it.

(a) $L_1 = \{a^n b^m : n\geq 0, m&gt;n\}$

(b) $L_1^3$

(C) $L_1^*$

I know the grammar for the language $L_1$, that is

$S \rightarrow aSb \mid bA$
$A \rightarrow bA \mid \epsilon$

please help me to find the grammars for another two languages.
b) Introduce a new start symbol $S_1$ and a new production rule $S_1 \rightarrow SSS$

c) Introduce a new start symbol $S_2$ and a new production rule $S_2 \rightarrow S_2S \mid \epsilon$