I think admins are too lazy to approve my queries…! All i wanted to ask that can we be given a series in which the right brackets repeat lik -1 1 -2 2 1…?? I think this question is perfectly under the guidelines of the contest…!!
I think, that golden rule is applied here - if it’s not forbidden in problem statement, it’s allowed 
Just my opinion, I haven’t solved the problem yet…
i think you can use any number anywhere (as any bracket anywhere like- ()}[()]{} ) but at the end of the day you should have to be confirmed that is it balanced or not???