Given a positive integer n, find the smallest integer which has exactly the same digits existing in the integer n and is greater in value than n. If no such positive integer exists, return -1.
Note that the returned integer should fit in 32-bit integer, if there is a valid answer but it does not fit in 32-bit integer, return -1.
Example 1:
Input: n = 12 Output: 21
Example 2:
Input: n = 21 Output: -1
Constraints:
1 <= n <= 231 - 1