For a two-digit number, the sum of the ones and tens digits is 9. If this two-digit number is subtracted from 27, then the difference obtained is exactly the original number and tens digits exchanged. Find the original number.
一个两位数，个位与十位上的数字的和是9．如果这个两位数减去27，那么得到的差正好是原来的数个位与十位数字交换．求原来的数．
<result>63</result>