While providing easier access to product information and ordering, online SCs may face more than expected product returns. This may be mainly due to the lack of customers feeling and touching the product before they purchase it. As an added service, an online retailer wants to respond reasonably fast to the customers requests and questions about their product returns or any other complaints. Customers send emails to the customer service help desk every 2 minutes, on average, and the standard deviation of the interarrival time is 10 minutes. It takes a staff member on average 8 minutes to write a response email and the standard deviation of the processing times is 5 minutes. If the retailer desires the response time to emails (time between the receipt of and the replying to the email) to be less than half an hour, determine the minimum number of staff members in the service help desk to be employed solely for responding to customer emails.