Start from integer 1, remove any integer that contains 9 such as 9, 19, 29...
So now, you will have a new integer sequence: 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, ...
Given a positive integer n, you need to return the n-th integer after removing. Note that 1 will be the first integer.
Example 1:
Input: 9 Output: 10
Hint: n will not exceed 9 x 10^8.
[Math]