Problem Description
For this problem, you will create a standard undo function.
An undo function allows a user to reverse or unperform the effect of an earlier action.
Input Format
The input file consists of logs describing a series of actions performed. The logs may contain the string "Ctrl+Z" in which case you would have to undo the most recently performed action.
Output Format
Output a single string - the currently latest action performed after all actions and undos. If there are no available actions to undo after the series of operations, print "No actions in clipboard." without the quotations.
Constraints
Each action log A is 1<|A|<50
Log file L will consist of t lines where 1<t<100.