The demand for next year's calendar at a bookstore is assumed to be normally distributed with a mean of 430 and a standard deviation of 70. The calendar costs the bookstore $7.00 each and will be sold for $11.00 each. Any calendars remaining for sale after the new year will be discounted and sold for $1.30 each. The bookstore believes ALL the remaining calenders to be sold after the new year will be sold at the $1.30 price. How many calendars should the bookstore stock if it wants to maximize its expected profit from calendars?