<s>[INST] Angela's Beauty Parlor has six workers: Arin, Jose, Kai, Lisa, Rohan, and Shin. Two of them are going on vacation during the next month and Angela wants to fill their shifts with the remaining four workers, with the constraint that the person covering must work the same days as the vacationer. Therefore, each shift has to be assigned to one of the four remaining workers, with the possibility of a worker being assigned more than one shift.

(a) How many possibilities are there for choosing the shifts to be covered by each of the four workers, with no further constraint?[/INST]