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题目描述

Mr Aoligei was playing with a string \(s\) written in the computer. The string has brackets and letters inside which he thought it was funny. He likes the string. Then, a hacker hacked his computer. The string was damaged, and he needs to find out How many pairs of brackets are in his string in order to find his string.

Note: "()" is a pair of brackets, but ")(" is not.

输入格式

Input is given from Standard Input in the following format:
\[{\large s}\]

输出格式

print the number of pairs of brackets in the string.

输入输出样例

Input #1

(o)8<))

Output #1

1