A series of $$$num$$$_$$$operations$$$ are performed on a string $$$initial$$$_$$$string$$$ of length $$$n$$$ that contains lowercase English letters only. In the $$$i$$$th operation, the prefix of the string of length $$$i$$$ is reversed. The final string thus formed is represented by $$$final$$$_$$$string$$$.

Given the string $$$final$$$_$$$string$$$ and an integer $$$num$$$_$$$operations$$$, find the initial string on which the operations were performed.

$$$\bf Example:$$$

Suppose $$$final$$$_$$$string$$$ = "chakerrank" and $$$num$$$_$$$operations$$$ = 3.

Then the initial string will be "hackerrank".

On the first operation, reverse "h" -> "hackerrank"

On the second operation, reverse "ha" -> "ahckerrank"

On the third operation,Reverse "ahc" -> "chakerrank" which is equal to $$$final$$$_$$$string$$$.