A retailer purchases a seasonal product from a supplier for $2/unit, which it then sells to customers for $10. Customer demand for the season is forecasted to be a normal distribution with a mean of 2,000 and a standard deviation of 250. If the retailer orders once from the supplier before the start of the selling season and salvages unsold units after the end of the selling season for $1/unit, what is the retailer's optimal expected profit in dollars