What is the way to find value inside the brackets using excel formulas? For example:

Column A
=======
abc.zyx(hurry)
888 abc(hello world((hurry))
google;defgh(abc(hello world(hurry up)))
klmn;bible(okay)
-2823.gggg; defgh(abc(hello world(no problem!)))

The return value are:
Column B
=======
hurry
hurry
hurry up
okay
no_problem!


Regards,
Roger