Suppose you will receive $15,000 in 10 months and another $12,000 in 21 months. If the discount rate is 5% per annum (compounding monthly) for the first 13 months, and 13% per annum (compounding monthly) for the next 8 months, what single amount received today would be equal to the two proposed payments? (answer to the nearest whole dollar; dont include the $ sign or commas)