A hospital uses methicillin, an antibiotic, in its daily operations. Demand for the antibiotic is normal with a mean of 43 pills a day and a standard deviation of 19 pills per day. It takes the supplier for the hospital 9 days to ship an order to the hospital once the order is made; the standard deviation for this lead time is 1 day. The hospital insists on a service level of 99.9%. What is the minimum safety stock that the hospital uses for the antibiotic?