The demand for a medical equipment is uncertain and follows a normal distribution. Its average daily demand is 48 units, with a daily standard deviation of 4 units. It costs $66 to place an order, and it takes 1 weeks to receive the order. The equipment requires a 95% service level, or a 95% probability of not-stocking-out. What would be the safety stock level to satisfy the required 95% service level? Note that z = normsinv(0.95) - 1.64. Numbers only, keep 3-decimal if not exact, either round up or down is ok