A department store needs to hire holiday season sales staff for their store. To cover all the responsibilities, they know that they need to have at least 20 workers on Sundays, 15 on Mondays, 16 on Tuesdays, 16 on Wednesdays, 16 on Thursdays, 22 on Fridays, and 22 on Saturdays. At a minimum, how many staff members need to be hired in order to ensure that the store can remain fully staffed every day of the week? Formulate an Integer LP (ILP) for this problem in Excel. Solve your model for the optimal solution