For a two-digit number, the sum of the ones digit and the tens digit is 7. If the ones digit and the tens digit of this number are reversed, the new two digits obtained are 9 greater than the original two digits, then the original two digits What is the number of digits.
一个两位数，个位数字与十位数字的和是7，如果把这个数的个位数字与十位数字对调，得到的新两位数比原来的两位数大9，那么原来的两位数是多少．
<result>34</result>