# [Japt](https://github.com/ETHproductions/japt) [`-h`](https://codegolf.meta.stackexchange.com/a/14339/), 14 [bytes](https://en.wikipedia.org/wiki/ISO/IEC_8859-1)

Outputs `undefined` instead of `0` (pending confirmation).

    ã ke"%(%)" mÊÍ

[Try it](https://petershaggynoble.github.io/Japt-Interpreter/?v=1.4.6&flags=LWg&code=4yBrZSIlKCUpIiBtys0&input=IigpKCgpKSI)

## 9 bytes

This version takes input as a string of `1`s & `0`s, representing `(` & `)` respectively, which the comments on the challenge would seem to allow.

    ã keA mÊÍ

[Try it](https://petershaggynoble.github.io/Japt-Interpreter/?v=1.4.6&flags=LWg&header=ciIlKCIxIHIiJSkiVA&code=4yBrZUEgbcrN&input=IigpKCgpKSI)

    ã ke"%(%)" mÊÍ     :Implcit input of string
    ã                  :Substrings
      k                :Remove items that return truthy (non-empty string)
       e               :  Recursively replace
        "%(%)"         :  RegEx /\(\)/ (or A=10, in the second version)
               m       :Map
                Ê      :  Length
                 Í     :Sort
                       :Implicit out output of last element