Yours would fail if you have 10 or more nested parens.
It won't any more, I made the minimal correction that solved this and I hope you will apologize me for not having pointed out explicitly having done so (but it's really a one-char correction).

Incidentally, to be fair I'm not really sure if with input strings limited to 20 chars (as of the rules!!) you can have more than 10 nested parens and thinking about it one more second... no, you can't!

In reply to Re^3: Shuffling cards by blazar
in thread Shuffling cards by amnesty_puppy

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