$($a$)$ Compute the running time of NaiveExp assuming that it takes O$($n log n$)$ to multiply an n$-$bit by an

m$-$bit number provided n $>=$ m$.($Hint: You may use the fact that $$L

k$=1$ k log k $=$ O$($L$2$ log L$).)$

$($b$)$ Compute the running time of FastExp assuming that it takes O$($n log n$)$ to multiply an n$-$bit by an m$-$bit

number provided n $>=$ m