Specify the mask you would need to inspect bit 4 of the unknown number. The result of the operation should be 0 (0x0000) if bit 4 is 0, and non-zero if bit 4 is 1. Express it as a 4-digit hexadecimal number.

Description: write function lastfirst() that takes one argument—a list of strings of the format "lastname, firstname" —and returns a list consisting of two lists: (a) a list of all the last names (b) a list of all the first names