Determine whether or not the following languages are regular.

a$)$ L$=[$a$^$n b$^$m: n $>=1\}$U$\{$a$^$n b$^$m: n$<=1,$m $>=1\}$

b$)$ L$=\{$a$^$n b$^$n$>=1\}$U$\{$a$^$n b$^$n$+2$: n$>=1\}$