For a two-digit number, the sum of the ones digit and the tens digit is 9. Swap the ones digit and the tens digit to get a new two-digit number, which is 9 more than the original number. Find the two-digit number ．
一个两位数，个位与十位上数字的和是9，将个位上的数与十位上的数调换，得到一个新的两位数，比原数多9，求这个两位数．
<result>45</result>