Find a context-free grammar for the following language (with n ≥ 0, m ≥ 0):

L = {a^{n}ww^{R}b^{n} : w ∈ {a, b} ∗ , n ≥ 1}.

S -> a S b | W

W -> a W a | b W b | $\epsilon$

First using S, get equal a and b then terminate it with palidrome which is given by W.