题目描述
A sequence of brackets is called balanced if one can turn it into a valid math expression by adding characters "+" and "1". For example, sequences "(())()", "()" and "(()(()))" are balanced, while ")(", "(()" and "(()))(" are not.
You are given a string which consists of opening and closing round brackets. Check whether it is a balanced bracket sequence.
Input
The only line of input contains a string between 1 and 100 characters long, inclusive. Each character in the string will be "(" or ")".
Output
Output "YES" if the bracket sequence is balanced, and "NO" otherwise (quotes for clarity only).
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
(()(()))()
样例输出
YES