For a two-digit number, the ones digit is 1 less than the tens digit, and a new two-digit number is obtained by exchanging the ones digit and the tens digit. The sum of the original number and the new number is 77. What is the two-digit number?
一个两位数，个位数字比十位数字小1，把个位数字和十位数字交换位置后得到一个新的两位数．原数与新数相加的和是77，这个两位数是多少．
<result>43</result>