Construct a context$-$free grammar that generates the following language:

L $=\{$wwR : w in $($a U b$)*\}$

Yan$$t$$n$$z:

S $->$ aSa $|$ bSb $|$ a

S $->$ aSa $|$ bSb

S $->$ aSb $|$ bSa $|\backslash$epsi

S $->$ aSa $|$ bSb $|$ b

S $->$ aSa $|$ bSb $|\backslash$epsi