Two wealthy grandparents want to set aside a large sum of money today in order to pay for their granddaughters private school tuition. Their granddaughter will start school six years from now, and the grandparents will have to cover twelve years of tuition (1st grade through 12th grade). Tuition is expected to cost $15,000 per year, and interest rates are currently 6%. If the grandparents want to set aside enough today to cover all twelve years of tuition expenses, how much should they set aside?