It’s probably adding compilation time, because a system that runs my python regex in 40ms should probably run this rust program in less than 1ms

deleted by creator

python 3 using regex:

import re
i=input()
p=r'(?:\(\)|\{\}|\[\])'
while re.search(p,i):
 i=re.sub(p,'',i)
print(i)

edit: made it uglier for the least characters challenge