Implement the following functions

using $81$ multiplexers

a$)F_1={\displaystyle \underset{m}{\overset{.}{}}}(1,3,5,7,8,9,11,13,15)$

b$)F_2={\displaystyle \underset{m}{\overset{.}{}}}(0,2,3,4,5,11,12,14,15)$

Please include all necessary diagrams for the solution $($Preferably using pen and paper$)$