A. Unusual Competitions

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A. Unusual Competitions time limit per test 1 second memory limit per test 512 megabytes input standard input output standard output A bracketed sequence is called correct (regular) if by inserting "+" and "1" you can get a well-formed mathematical expression from it. For example, sequences "(())()", "()" and "(()(()))" are correct, while ")(", "(()" and "(()))(" are not. 扫描二维码关注公众号，回复： 10229194 查看本文章 The teacher gave Dmitry's class a very strange task — she asked every student to come up with a sequence of arbitrary length, consisting only of opening and closing brackets. After that all the students took turns naming the sequences they had invented. When Dima's