An Internet retailer stocks a popular electronic toy at a central warehouse that supplies the West Africa sub-region. Every week, the retailer makes a decision about how many units of the toy to stock. Suppose that weekly demand for the toy is approximately normally distributed with a mean of 2500 units and a standard deviation of 300 units. If the retailer wants to limit the probability of being out of stock of the electronic toy to no more than 2.5% in a week, how many units should the central warehouse stock?