Get the next largest number.

### Description:
Given a number n, find the smallest number that has same set of digits as n and is greater than n. If x is the greatest possible number with its set of digits, then print “not possible”.
ex:
Input: n = "1234"
Output: "1243"

Input: n = "4321"
Output: "Not Possible"

### Details
Technical Specification: Solution to the code in C, C++, Python, JavaScript is accepted.
Type of Issue: Single
Time Limit: 1 day (from the moment the issue has been assigned to someone)
### Directory Structure
Create a folder named "Greater-number" in the Algorithms folder and submit the code file.

Note
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Once you are done with the task and have created a Pull Request, please tag @sravanireddy1102 to request a review.